FINAL INVESTIGATION REPORT ON SERIOUS
INCIDENT TO M/s GO-AIR AIRBUS A320
AIRCRAFT VT-WGR AT BENGALURU
AIRPORT ON 11/11/2019
R.S. PASSI
INVESTIGATOR-IN-CHARGE
KUNJ LATA CAPT GAURAV PATHAK
INVESTIGATOR INVESTIGATOR
FOREWORD
In accordance with Annex 13 to the Convention on International Civil Aviation
Organization (ICAO) and Rule 3 of Aircraft (Investigation of Accidents and
Incidents), Rules 2017, the sole objective of the investigation of an accident
shall be the prevention of accidents and incidents and not to apportion blame
or liability.
This document has been prepared based upon the evidences collected
during the investigation, opinion obtained from the experts and ATC
recordings. Consequently, the use of this report for any purpose other than
for the prevention of future accidents or incidents could lead to erroneous
interpretations.
ABBREVIATIONS
AAIB
Aircraft Accident Investigation Bureau
ACC
Area Control
ADC
Aerodrome Control
APP
Approach Control
ATC
Air Traffic Controller
ASR
Approach Control Surveillance Approach Radar
ATPL
Airline Transport Pilot License
CPL
Commercial Pilot License
DFDR
Digital Flight Data Recorder
DME
Distance Measuring Equipment
FATA
Foreign Aircrew Temporary Authorization
ICAO
International Civil Aviation Organization
IFR
Instrument Flight Rule
NM
Nautical Miles
SMGCS
Surface Movement Guidance and Control System
UTC
Co-ordinated Universal Time
VHF
Very High Frequency
VOR
VHF Omnidirectional Range
TABLE OF CONTENT
Sl. No.
Subject
Page
SYNOPSIS
1
1.0
FACTUAL INFORMATION
2
1.1
HISTORY OF FLIGHT
2
1.2
INJURIES TO PERSON
3
1.3
DAMAGE TO AIRCRAFT
3
1.4
OTHER DAMAGES
4
1.5
PERSONAL INFORMATION
4
1.5.1
Pilot-in-Command
4
1.5.2
Co-Pilot
5
1.6
AIRCRAFT INFORMATION
6
1.6.1
General
6
1.6.2
Post Flight Report (Maintenance)
7
1.7
METEOROLOGICAL INFORMATION
7
1.8
AIDS TO NAVIGATION
9
1.9
COMMUNICATION
9
1.10
AERODROME INFORMATION
11
1.11
FLIGHT RECORDERS
12
1.12
WRECKAGE AND IMPACT INFORMATION
16
1.13
MEDICAL AND PATHOLOGICAL INFORMATION
18
1.14
FIRE
18
1.15
SURVIVAL ASPECT
18
1.16
TEST AND RESEARCH
18
1.17
ONGANIZATIONAL AND MANAGEMENT
INFORMATION
18
1.17.1
Metrological Services at Bangalore
18
1.17.2
Airline Operator
22
1.18
ADDITIONAL INFORMATION
24
1.18.1
CAR Section 8 Series C Part I
24
1.18.2
A320 Auto-Land Capability in CAT 1
25
1.18.3
Flight Plan (first page)
27
1.18.4
Load and Trim Sheet
28
1.18.5
FCTW/FCOM references
28
1.19
USEFUL OR EFFECTIVE INVESTIGATION
TECHNIQUES
29
2.0
ANALYSIS
30
2.1
General
30
2.2
Meteorological and Environmental Aspects
30
2.3
ATC Management in Deteriorating Weather
31
2.4
Flight Operations
33
2.5
Aircraft Handling
36
2.6
Factors Leading to the Incident
45
3.0
CONCLUSION
47
3.1
FINDINGS
47
3.2
PROBABLE CAUSE
49
4.0
SAFETY RECOMMENDATIONS
50
FINAL INVESTIGATION REPORT ON SERIOUS INCIDENT OF M/s GO-AIR
A320 AIRCRAFT VT-WGR AT BENGALURU AIRPORT ON 11/11/2019
1.
Aircraft Type
Airbus A320
2.
Nationality
INDIAN
3.
Registration
VT-WGR
4.
Owner
GO-AIR
5.
Operator
GO-AIR
6.
Pilot – in –Command
ATPL/FATA HOLDER
Extent of Injuries
NIL
7.
Co-Pilot
CPL
Extent of Injuries
NIL
8.
Place of Incident
BANGALORE
9.
Co-ordinates of Incident
Site (Location)
13.1986° N, 77.7066° E
10.
Last point of Departure
NAGPUR
11.
Intended place of
Landing
BANGALORE
12.
Date & Time of Incident
11/11/2019 AT 0152 UTC
13.
Extent of Injuries
NIL
14.
Phase of Operation
LANDING
15.
Type of Incident
SERIOUS INCIDENT
(ALL TIMINGS IN THE REPORT ARE IN UTC)
1
SYNOPSIS
A Serious incident occurred at Bangalore airport on 11/11/2019 at 0152 UTC of
M/s Go-Air (Type -A320, Registration- VT-WGR).
Aircraft drifted to left of the Runway 09 and touched unpaved surface. After
touching the ground for few seconds, aircraft made a missed approach due to
which main undercarriage touched the unpaved surface resulting in stall of Engine
no 1.
The aircraft made an approach into Bangalore in deteriorating weather conditions
and carried out missed approach due to loss of visual reference in low visibility
conditions. Aircraft diverted and landed in Hyderabad.
The occurrence was classified as a “Serious Incident” in accordance with the
Aircraft (Investigation of Accidents and Incidents) Rules, 2017. DG, AAIB ordered
an investigation into this occurrence vide Order INV-12011/23/2019-AAIB
dated11/11/2019.
2
1.0 FACTUAL INFORMATION
1.1 History of the flight
On 11
th
November 2019, an Airbus 320 aircraft VT-WGR was involved in a Serious
Incident while operating flight from Nagpur to Bangalore (VOBL). The scheduled
departure time of the flight from Nagpur was 00:35 UTC with a flying time of 01:21
hours. The flight departed Nagpur at 00:24 UTC.
The aircraft made an approach into VOBL in deteriorating weather conditions and
carried out a missed approach due to loss of visual references in low visibility.
During missed approach, main undercarriage of the aircraft contacted the unpaved
surface (kutcha) by the side of runway (within the aerodrome), followed by engine
1 stall during the missed approach. After holding for some time over VOBL, the
aircraft diverted to Hyderabad (VOHS) and carried out a safe landing at VOHS.
The Serious Incident occurred at 01:52 UTC.
Prior to operation of flight, remote preflight briefing was held at Nagpur by the flight
crew. The briefing included weather at destination airport and alternate. The
visibility at the destination was forecast at 2000 meter and a TEMPO reduction of
800 meters in Fog.
PIC was pilot flying (PF) for takeoff and landing and for the remaining phase of
flight, the Co-pilot was the pilot flying. As per DATIS, the weather at VOBL at the
time of approach was light winds, visibility of 200 meters, RVR as 1500 meters in
Fog and cloud base reported was broken at 200 feet. The flight till approach into
VOBL was uneventful. When the flight was with Approach Radar Control and the
aircraft was being vectored for Runway 09, visibility and RVR were decreasing.
At 01:44:34 UTC, Radar controller transmitted “All Station Visibility 200 meters and
RVR 1200 meters”. After this, no weather update was passed on by ATC. At
01:46:41 UTC, the flight was cleared for ILS approach Runway 09 and after
establishing on Localizer, it was changed to tower. Though there was a
3
progressive drop in the visibility, the tower controller also did not pass the current
RVR and visibility, when the incidented flight was on final.
The PIC took over as PF and commenced approach. The aircraft was stabilised
on the instrument landing system above 1000 feet AFE. The PF disconnected the
Autopilot at 220 feet Radio Altitude for a manual landing. During the flare
manoeuvre, he consistently applied aft side stick commands and the aircraft
floated above the ground for duration of about 8 seconds while the thrust levers
were brought to idle. 02 seconds prior to contact, at 20 feet RA the First Officer
announced “Go Around” and the PF initiated a Go Around. The Aircraft contacted
the unpaved surface on the left side of the runway (within the aerodrome) during
the Go Around manoeuvre.
Subsequently, the left engine stalled due to foreign object ingestion during the
transient touchdown on the unpaved surface (Kutcha), causing thrust reduction
from the affected engine. The aircraft took up a holding pattern over Bangalore
and subsequently diverted to Hyderabad since there was no weather improvement
at Bangalore. The aircraft landed safely at Hyderabad.
1.2 Injuries to Persons
Injuries
Crew
Passengers
Others
Fatal
Nil
Nil
Nil
Serious
Nil
Nil
Nil
Minor/None
06
175
Nil
1.3 Damage to the Aircraft
During walk around inspection at Hyderabad, mud and grass was observed on
both LH & RH MLG wheels and brakes, No other external damage or abnormality
was noticed. Externally, there were no signs of any FOD on engines. There was
no damage on landing gear. Extension/ Retraction and free fall checks were
satisfactory.
4
A full Bore Scope Inspection (BSI) of both engines was carried out. On ENG#1
heavy rub marks were observed on HPC Rotor 7 and 8 Outer Air seal. There was
spallation of HPC Stator 7 Inner Air seal.
There were no observations based on the BSI of Engine #2.
1.4 Other damages
Nil
1.5 Personnel Information
1.5.1 Pilot-in-command (PF at the time of occurrence)
Age
61 years
License
ATPL/FATA
5
Date of Issue
21-May-18
Valid up to
11-Apr-20
Category
Multi Engine (Cat-1)
Date of Class I Med. Exam.
19-Aug-19
Class I Medical Valid up to
01-Mar-20
Date of issue FRTOL License
21-May-18
FRTO License Valid up to
11-Apr-20
Endorsements as PIC
A-320
Total flying experience
20427 hours
Total flying experience on type
8568 hours
PIC experience on type
6249 hours
Last Flown on type
09-Nov-19
Total flying experience during last 30 days
58:44 hours
Total flying experience during last 24 Hours
04:27 hours
Rest period before flight
26:23 hours
1.5.2 Co-Pilot (PM at the time of occurrence)
Age
25 years
License
CPL
Date of Issue
10-Sep-15
Valid up to
09-Sep-20
Category
Multi engine
Date of Class I Med. Exam.
23-Jul-19
6
Class I Medical Valid up to
20-Aug-20
Date of issue FRTOL License
10-Sep-15
FRTO License Valid up to
09-Sep-20
Total flying experience
325:45 hours
Total flying experience on type
109:20 hours
Last Flown on type
09-Nov-19
Total flying experience during last 30 days
72:27 hours
Total flying experience during last 24 Hours
04:27 hours
Rest period before flight
26:23 hours
1.6 Aircraft Information
1.6.1 General
Aircraft Model
A320-271N
Aircraft S. No.
MSN 08209
Year of Manufacturer
2018
C of R
Valid
C of A
Valid
Category
NORMAL
A R C Validity
Valid
Maximum Take-off weight
79000 KG
Last major inspection
A4 Check
List of Repairs carried out after last major inspection
till date of incidence
No Major repairs or
inspection
7
1.6.2 Post Flight Report (Maintenance)
1.7 Meteorological Information
Bangalore airport experiences light fog during October-November and dense fog
mostly during November-December-January. Sudden changes in visibility and
RVR being recorded is a common phenomenon during this period. Fog onset
usually occurs between 1800 and 0300 UTC and its formation is less likely
thereafter.
At Bangalore airport, visibility & RVR are continuously recorded through a software
(Drishti) which has a refresh rate of 10 seconds. Latest Weather Report of the
airport, together with trend forecast valid for the next 2 hours is also
8
broadcast on ATIS. As per Bangalore Metrological Department records, METARs
were issued at 0130 UTC and 0200 UTC. In between, a SPECI was also issued at
0153 UTC.
Time
(UTC)
0130
0153 (Speci)
0200
Wind
040 Degree/ 03 Kts
070 Degree/ 05 Kts
070 Degree/ 04 Kts
Visibility
200 M
100 M
50 M
RVR (09)
1500 M
125 M
125 M
QNH
1016
1016
1016
WEATHER
Haze
Haze
Haze
TREND
No Significant
Change
No Significant
Change
No Significant
Change
Following are the relevant real time recordings by the software system. The
shaded row shows the time of the Incident
S. No.
Time IST (HH/MM/SEC)
Time UTC(HH/MM/SEC)
RVR (Meter)
1
07:06:33
01:36:33
1200
2
07:07:13
01:37:13
800
3
07:10:43
01:40:43
600
4
07:10:53
01:40:53
500
5
07:11:33
01:41:33
175
6
07:11:53
01:41:53
125
7
07:23:00
01:53:00
125
The Terminal Area Forecast at the time of departure was as follows (of
11.11.2019):
Between 0000 to 0900 UTC - VRB 02KT 2000 BR SCT004 SCT012 TEMPO
Between 0000 to 0300 UTC - FG 800 BKN 002 SCT012 BECMG
Between 0400 to 0500 UTC - 6000 SCT012
9
1.8 Aids to Navigation
Frequencies of navigational aids at Bangalore are as below: -
Navigation Aid
Frequency
LLZ 09 (IBAN)
109.3 MHz
GP 09
332.0 MHz
DVOR I (BIA)
116.8 MHz
DME I
1139/1202 MHz
DVOR (BIB)
114.5 MHz
DME
1179/1116 MHz
ILS DME 09 (Co-located with GP 09)
1054/991 MHz
As per the requirements, flight navigation systems must be regularly calibrated,
inspected and maintained to ensure that all essential navigation aids for pilots are
always working properly. Accordingly, ILS calibration was at Bangalore was done
on 27-5-2019 which was valid till 27-11-2019.
1.9 Communication
Two-way communications between the ATC units and the aircraft was always
maintained. Relevant portion of tape transcript of Approach (127.75 MHz) is as
below: -
TIME
CHANNEL
013358
ASR
IGO 909, VISIBILITY 200 METERS AND RVR FOR
RUNWAY 09 1500 METERS
013405
IGO909
RADAR COPIED 909
013423
ASR
SEJ1035 DESCEND TO FLIGHT LEVEL 120
013426
SEJ1035
DESCEND 120 SEJ1035
013428
ASR
AND VISIBILITY 200 METER
014048
ASR
GOW811 DESCEND TO FLIGHT LEVEL 80
10
014051
GOW811
MAM DESCEND TO 80 GOW811
014151
ASR
GOW811 DESCEND TO 7000 FEET QNH 1016
TRANSITION LEVEL FLIGHT LEVEL 80
014157
GOW811
DESCNED 7000 1016 QNH TRANSITION FLIGHT
LEVEL 80 GOW811
014226
ASR
GOW811 REDUCE SPEED TO 210 KNOTS
014228
GOW811
SPEED 210 GOW811
014311
ASR
GOW811 DESCEND TO 5900 FEET
014314
GOW811
5900 FEET GOW811
014316
ASR
25 MILES FROM TOUCHDOWN REDUCE SPEED TO
180 KNOTS
014436
ASR
ALL STATIONS VISIBILITY 200 METERS, RVR 1200
METERS
014637
ASR
GOW811 LEFT HEADING 120 CLEARED FOR ILS
APPROACH RUNWAY09
014641
GOW811
LEFT 180 CLEARED FOR ILS 09 GOW811
014757
ASR
GOW811 ON LOCALIZER
014802
GOW811
GOW811 ON ILS MAM
014804
ASR
ROGER 10 MILES FROM TOUCHDOWN CONTACT
TOWER 124.35
Relevant portion of tape transcript of Tower on frequency 124.35 MHz
TIME
CHANNEL
014623
SEJ1035
TOWER NAMASKAR SEJ1035 ON ILS 09 MILES
014637
SEJ1035
CLEARED TO LAND 09 CORRECTION CONTINUE
APPROACH SEJ1035
014737
TWR
SEJ1035 RUNWAY09 CLEARED TO LAND WIND
CALM
014741
SEJ1035
CLEARED TO LAND 09 SEJ1035
11
014832
GOW811
TOWER GOW811 NAMASKAR ON FINAL
014836
TWR
GOW811 BANGALORE TOWER NAMASKAR
CONTINUE APPROACH RUNWAY09 WIND CALM
014840
GOW811
CONTINUE APPROACH GOW811
014921
SEJ1035
GOING AROUND
014931
TWR
SEJ1035 CONFIRM GOING AROUND
015001
TWR
GOW811 RUNWAY09 CLEARED TO LAND WIND
CALM
015006
GOW811
CLEARED TO LAND RUNWAY09 GOW811
015217
TWR
GOW811 CONFIRM GOING AROUND
015220
GOW811
BANGALORE GOW811 GOING AROUND
015222
TWR
GOW811 ROGER CLIMB INITIALLY 7000 CONTACT
AND APPROACH RADAR 127.75
015228
GOW811
12775 GOW811
1.10 Aerodrome Information
Bangalore Airport (Kempegowda International Airport (IATA: BLR, ICAO: VOBL)),
is owned and operated by Bangalore International Airport Limited (BIAL). It has got
a single Runway with orientation as 09/27. The dimensions of runway are 4000 m
x 45 m. Runway 09 is installed with ILS and is a CAT I runway with only runway
edge lights available. It does not have center line lights.
12
Missed approach procedure at Bangalore airport
The Bird Chaser who was positioned near A-8 northern shoulder (shown by red
dot) reported that at the time the aircraft touched down, the visibility was low with dense
fog. He could not see the aircraft but heard the sound of engines which was very loud.
The Bird chaser immediately reported to the shift in-charge that an aircraft has flown just
above his location.
1.11 Flight Recorders
The CVR recording was available and has been used for investigation purposes.
In addition to FDR analysis, the FDR readout was also shared with the OEM
(Airbus) and a handling report was received from them. The following is the factual
data information from the report. The aircraft carried out an ILS approach to runway
09 at Bangalore.
At 1000 ft RA (01:50:40 UTC),
The aircraft configuration was
>
Gross weight - 65.2t
>
CG at 30.6%
>
Aircraft in CONF FULL with Slats as 27° & Flaps as 40°
>
Landing gear selected down
13
>
Ground spoilers armed
>
Auto-brake “LOW” mode was armed
Both autopilots (APs) and Flight Directors (FDs) were engaged in “G/S” (vertical)
and “LOC” (lateral) modes.
Speed
>
Auto-thrust (A/THR) was active in “SPEED” mode
>
Recorded VLS was 128kts
>
Speed target was managed at 136kts (VLS+8kts)
>
CAS was 136kts (speed target).
Attitude and trajectory
>
Rate of descent was approximately 700ft/min
>
Pitch angle was +2.5° (nose up)
>
Heading was 091°
>
Drift angle was +1° (aircraft nose toward the left of the track)
>
The aircraft was on the glide slope and the localizer
From 1000ft RA (01:50:40 UTC) to APs disengagement at 220ft RA (01:51:46
UTC)
On the longitudinal axis
>
Pitch angle varied between +2.5° and +3.5° (nose up)
>
Speed target was managed at 136kt
>
CAS varied between 135kt (speed target-1kt) and 137kt (speed
target+1kt)
>
Rate of descent varied between 750ft/min and 650ft/min
>
No significant vertical load factor variation
>
Aircraft was on the glide slope
On the lateral axis
>
No significant variations on aircraft lateral axis
>
Aircraft was stabilized on the localizer
14
From APs disengagement (01:51:46 UTC) to flare initiation at 45ft RA
(01:51:59 UTC),
On the longitudinal axis
>
CM1 nose-up side-stick input reached ~1/5 of full nose-up deflection
▪
Pitch angle was around +3.0° (nose up)
>
Rate of descent varied between 700 ft/ min and 600 ft/ min
>
No significant vertical load factor variation
>
Speed target was still managed at 136kt
>
CAS varied between 135 kts (speed target-1kt) and 137 kts (speed
target+1kt)
>
Aircraft was on the glide slope
On the lateral axis
>
CM1 side stick input reached ~1/5 of full left deflection
▪
Roll angle reached -3.5° (left wing down)
>
No significant rudder pedal input was applied
>
Heading varied between 089° and 092° (QFU 092°)
>
No significant drift angle
>
No significant lateral load factor variation
>
Aircraft was on the localizer
From flare initiation at 45ft RA (01:51:59 UTC) to touchdown (01:52:15 UTC)
On the longitudinal axis
>
At ~45ft RA, flare was initiated by CM1 with a ~2/3 of full nose-up input
followed by a continuous nose-up order up to ~4/5 of full deflection
v'
Pitch angle increased step by step from +3° to +6°, then to +7.5°
and finally to +8.5°.
>
Vertical load factor increased from +1.00G to +1.15G then decreased to
+0.90G before increasing again up to +1.00G.
>
Rate of descent decreased from 600ft/min to 100ft/min, then increased up
to 600ft/min before touchdown.
15
>
At 01:52:03 UTC (~25ft RA), thrust levers were retarded to “IDLE” leading
to A/THR disconnection.
>
CAS decreased from 136kt (speed target) to 120kt (speed target-16kt).
>
At 01:52:12 UTC (~20ft RA), a go-around was initiated as thrust levers
were pushed to “TOGA”.
On the lateral axis
>
CM1 side-stick input varied between ~1/3 of full left and half of full right
deflection.
v'
Left roll angle increased from -2° to -11° before decreasing to -1°
before touchdown.
>
Leftward rudder pedal inputs were applied up to ~1/4 of full deflection then
rightward rudder pedal orders were applied up to half of full deflection.
v'
Heading decreased from 089° to 078° then increased to 087° (QFU
092°).
v'
Drift angle increased from +1.0° to +4.5° (aircraft nose toward the
left of the track) then reversed to -8.0° (aircraft nose toward the
right of the track) reached at touchdown.
>
Lateral load factor varied between +0.05G and -0.10G.
>
Localizer deviation started to increase and reached ~3.5DOT to the left of
the localizer at touchdown.
At 01:52:15 UTC (Touchdown)
On the longitudinal axis
>
+8° of pitch angle.
>
-7ft/s (±2ft/s) of recalculated aircraft vertical speed.
>
+1.80G of vertical load factor.
>
CAS 120kt (VLS-8kt).
On the lateral axis
>
-1° of roll angle (left wing down).
>
087° of heading (QFU 092°).
>
-8° of drift angle (nose toward the right of the track).
16
>
-0.40G of lateral load factor.
From touchdown (01:52:15 UTC) to lift-off (01:52:19 UTC)
On the longitudinal axis
>
Main landing gears were recorded compressed for ~3.5s.
>
PF continued to apply a nose-up order up to full back stick. CM2 applied a
nose-up order up to ~1/3 of full deflection.
v'
Pitch angle reached +5.5° then started to increase.
>
Vertical load factor varied between +0.65G and +1.30G.
>
CAS was around 120kt (VLS-8kt).
>
Master Warning triggered on ground.
On the lateral axis
>
PF applied a right roll order up to ~3/4 of full deflection. CM2 applied some
slight
left roll orders.
v'
Roll angle reached -2° (left wing down) then reversed and right roll angle
increased.
>
Rightward rudder pedal order continued to be applied up to half of full deflection.
v'
Drift angle stabilized around -8.0° (aircraft nose toward the right of the
track).
>
Lateral load factor varied between -0.55G and +0.40G.
>
Localizer deviation continued to increase and up to ~4.5DOT to the left of the
localizer.
1.12 Wreckage & Impact Information
The images below show clear marks of the main gear rolling on the unpaved
surface (Kutcha).
There was also a pile of rubble and a tower which were in the offset trajectory of
the aircraft while it was on the ground.
The aircraft was airborne well before the tower and had turned right immediately
after getting airborne.
The tower would not have been visible to the crew given the prevailing visibility.
17
Tyre Marks
18
1.13 Medical & Pathological Information
The flight crew had undergone pre-flight medical examination at Nagpur prior to
take off. The Pre Flight Medical Report was satisfactory and Breath analyser test
was negative.
1.14 Fire
Nil
1.15 Survivable Aspect
The incident was survivable.
1.16 Test & Research
Nil
1.17 Organisational & Management Information
1.17.1 Meteorological Services at Bangalore
The Meteorological Services for civil aviation are provided by the India
Meteorological Department (IMD). At Bangalore Airport weather is available for 24
Hrs. As per procedure, METAR is issued every 30 minutes in which Time, Wind,
direction/ Speed, Visibility, RVR, Cloud, Trend etc is given. If some significant
change is observed in weather condition like change in Visibility, RVR or warning
etc a SPECI (Local special report) is issued in between METARs. Latest Weather
Report of the airport, together with trend forecast valid for the next 2 hours is
broadcasted on ATIS. Dristhi software is installed at the airport. It monitors real
time change in Visibility and RVR.
As per Meteorological Department records, METAR were issued at 0130 UTC and
0200 UTC when visibility and RVR were 200m/1500m and 50m/125m respectively.
In between the above METARs, a SPECI was also issued at 0153 UTC with
visibility and RVR as 100m/125m.
19
SPECI - Special METAR
A SPECI is the same as a METAR but issued when the following criteria is met
.
WIND :
1 Mean surface wind direction has changed by 60 degrees or more, the mean
wind speed before and/or after the change being 10Kt or more
2 Mean surface wind speed has change by 10Kt or more, in the latest METAR.
3 Wind Gusts have increased by 10Kt or more, the mean wind speed before
and/or after the change being 15Kt or more.
VISIBILTY
4. Visibility changes to or pass:
a Visibility 800,1 500,3 000 or 5000 meters
b. 550,1200,2000,2500,4000 meters Additional speci
5. Runway visual range (RVR) changes to or pass 150, 350, 600, 800m.
SIGNIFICANT WEATHER :
6 When any combination of weather in the significant begins,
ends or changes intensity.( Precipitation, thunderstorm, squall )
BASE OF THE CLOUD :
7. Height of the base of the lowest cloud layer of BKN or OVC extent,
changes to or passes.
a 100, 200, 500 or 1000 or 1500ft (30 or 60 or 150 or 300 or 450 meters)
When the amount of cloud below 1500ft changes from:
a. SKC, FEW, SCT to BKN or OVC
b BKN or OVC to SKC, FEW, SCT
TEMPERATURE:
9. Increase in temperature of 2 degrees Celsius or more.
RVR reporting
METAR : R09/0450 R27/0500 (4DIGITS )
MET REPORT RVR RWRY09 450M RWRY27 500M (3 DIGITS )
W1/W'
X:
ww Present wx
0
Half or less through
00 — cloud not observed/not visible
1
— more than half and less than half partly
01 becoming less
2
--- more than half through
02 no change
03 forming or developing
20
Drishti Display at Approach Controller:
A separate screen is kept at the approach controller station, where current weather
is displayed. A time lag of 82 seconds in the Dristhi display and actual UTC time
display was observed.
Time lag between actual UTC window and Dristhi display (Approach
position)
The Drishti Weather Display is not in clear line of sight for the approach controller.
The display is obstructed with shift folders placed between the approach controller
and the display. The controller would need to turn in order to view the display for
any weather change/ update.
21
Hindrance in Viewing Weather Screen
IMD has issued a circular for issuing a SPECI, which requires that whenever RVR
changes to or crosses the limits i.e. 150 m, 350 m, 600 m and 800 m. But in this
case, the SPECI was not issued at 0141 UTC when RVR decreased to 125 m. It
was found from real time weather pick up that RVR decreased from 1200 m to 125
m in about 5 1/2 minutes. At that time, the subject aircraft was changed over from
approach to tower.
Drishti Display at Tower Controller
A separate screen is kept in tower controller position, where current weather is
displayed and there is also a person who mans the position. Tower met officer
gives a hand written METAR /SPECI to the tower controller who in turn passes the
current weather to the aircraft. When the weather is deteriorating, a senior MET
officer is required to be present in the tower, but on investigation, it was found that
due to the shortage of manpower, this is often not done.
Obstruction
between controller
and Drishti screen
Drishti weather screen
22
1.17.2 Airline Operator
The Operator is a Scheduled Airline Service Operator and holds a valid
Permit. (A) Organisational Structure of the Flight Operations Department
As per the approved organisation structure for Flight Operations, the Director Flight
Operations (DFO) has all relevant support departments and functions reporting to
him. The position of a Vice President is placed above the DFO in reporting line to
the Accountable Manager. The reporting line for the DFO is dotted to the
Accountable Manager, while he remains a direct report to the Vice President Flight
Operations.
Monitoring of Weather Minima Violations by Flight Safety Department
As per the requirements, the Operators Flight Safety Department is required to
investigate all weather minima violation reports filed by operation department. All
arrival and departure messages (relevant to the occurrence) shall be appended
with the relevant METAR. These shall be assessed by the Chief of Flight Safety
and if any violations are noticed, the same should be communicated to DFO for
corrective action. Minima violation reports were not available with the Flight Safety
Department.
(B) Regulatory Oversight of the Operator
Special Audit Findings
A Special Audit was conducted on the Airline by the DGCA from 1
st
July 2019 to
4th July 2019. The DGCA observed two Level 1 findings and ten Level 2 findings.
A Corrective Action Report prepared by the Airline on 22 August 2019, was
submitted to the DGCA. As on 25
th
August 2020, the Airline had yet not received
confirmation on whether corrective actions taken by the airline via the report
submitted were acceptable to the DGCA.
23
Main Base Inspection
A Main Base Inspection by the DGCA was carried out from 22 July to 26 July 2019.
Vide their report dated 7
th
August 2019, serious concerns which included 12 Level
1 Findings and 54 Level 2 findings were raised. The target date for closure of the
audits was stated as 14 Aug 2019 for Level 1 and 07 September 2019 for the Level
2 findings. The Airline submitted a response dated 13 August 2019 which was
received at DGCA on 16 August 2019.
However, as on 25
th
August 2020, the Airline had yet not received confirmation on
whether corrective actions taken by the airline submitted through the ATR were
acceptable to the DGCA or not.
(C) Flight Planning at Dispatch
As per the Dispatch Manual, the duties and responsibilities of Flight Dispatcher
shall conform to CAR Series “M”, Section 7, Part II. He should have all information
latest by two hour prior to aircraft departure time.
• He has to collect the latest meteorological data from the concerned
agencies and thoroughly analyse the possible effects of the weather on the
route to be flown in the light of meteorological reports and forecasts for the
destination and alternate aerodromes; recent weather reports and
forecasts for the route and areas adjacent to it; and current weather charts.
• Ensure that a flight is planned to depart only when current meteorological
reports or a combination of reports and forecasts indicate that conditions
at the airport of intended landing, or where a destination alternate is
required, at least one destination alternate airport will, for a period of one
hour before and after the estimated arrival time, be at or above operating
minima.
• Ensure that before a flight is commenced, meteorological conditions and
expected delays are taken into account.
24
Flight Planning during FOG
During winter which is likely to cause disruption in flight operations mainly due
to FOG (Low Visibility), it is imperative that the Managers in the respective
shifts maintain a fog watch for flights in our network and notify OCC/ Rostering
via Email followed by telecom at least 24 hours in advance to enable them
roster CAT-III crew which can possibly avoid an unnecessary diversion. The
following points should be considered while sending a FOG watch message:-
a) Fog Watch is applicable for the next / approaching 12 hours.
b) Fog Watch is based primarily on the TAF and any other official Weather
source.
c) If the TAF is expected to fall below CAT 1 minima, the respective station
must alert crew scheduling, (local and Mumbai), in advance.
d) Nodal Officers nominated from time to time in Roster and Flight Dispatch is
to be intimated.
e) Fog Watch Email is to be originated by Manager-Flight Dispatch on a daily
basis for at time 1300 UTC for all the fog affected stations.
Adverse Weather Watch
An Adverse Weather Watch will continue to be maintained and emails generated
only for the station where adverse weather is prevalent OR forecasted.
1.18 Additional Information
1.18.1 CAR section 8 Series C Part I
(i) For Category I (CAT I)
A decision height not lower than 60 m (200 ft) and with either a visibility
not less than 800 m or a runway visual range not less than 550 m;
(ii) Para 4.5 Approach and Landing Conditions
Before commencing an approach to land, the PIC must satisfy himself/
herself that, according to the information available to him/her, the weather
25
at the aerodrome and the condition of the runway intended to be used
should not prevent a safe approach, landing or missed approach, having
regard to the performance information contained in the Operations Manual.
(iii) Para 4.6.1
The PIC shall not commence an instrument approach if the reported RVR/
Visibility is below the applicable minimum.
(iv) Para 4.6.2
If, after commencing an instrument approach, the reported RVR/ Visibility
fall below the applicable minimum, the approach shall not be continued:
(a) Below 1 000 ft above the aerodrome; or
(b) Into the final approach segment.
(v) Para 11.3.6: VISUAL REFERENCE
A pilot may not continue an approach below MDA/MDH unless at least one
of the following visual references for the intended runway is distinctly visible
and identifiable to the pilot
(a) Elements of the approach light system;
(b) The threshold;
(c) The threshold markings;
(d) The threshold lights;
(e) The threshold identification lights;
(f) The visual glide slope indicator;
(g) The touchdown zone or touchdown zone markings;
(h) The touchdown zone lights;
(i) Runway edge lights
1.18.2 A-320 Auto-land Capability in CAT 1
As per the Airbus 320 Flight Crew Technique Manual, the crew are advised to plan
the approach using the best approach capability available. This is normally the
CAT 3 DUAL with Auto-land depending on the aircraft status. The crew then
assess the weather and plan a possible downgrade capability if applicable. For
26
Bangalore Runway 09, the approach category would be CAT 1 ILS and the aircraft
would have been flown down to CAT 1 ILS minimum Altitude to sight the runway
and continue for either a manual or automatic landing (Auto-Land).
The FCTM extract below states the Auto-land capability for CAT 1 as possible with
precautions.
APPROACH STRATEGY (FCTM)
Regardless of the actual weather conditions, the crew should plan the approach
using the best approach capability. This would normally be CAT 3 DUAL with
Autoland, depending upon aircraft status. The crew should then assess the weather
with respect to possible downgrade capability.
The precautions in the table above are explained in FCOM Limitations chapter.
“Automatic landing system performance is demonstrated with CAT II or CAT III
ILS/MLS airport installation. However, automatic landing in CAT I or better weather
conditions is possible on CAT I ground installations or on CAT II/III ground
installations when ILS/MLS sensitive areas are not protected, if the following
precautions are taken:
• The airline checked that the ILS/ MLS beam quality, and the effect of the
terrain profile before the runway has no adverse effect on AP/FD guidance.
Particularly, the effect of terrain profile within 300 m before the runway
threshold must be evaluated
• The flight crew is aware that LOC or G/S beam fluctuations, independent of
the aircraft system, may occur. The PF is prepared to immediately
disconnect the autopilot, and to take the appropriate action, should not
satisfactory guidance occur
27
•
At least CAT2 capability is displayed on the FMA and the flight crew uses
CAT II/III procedures
•
Visual references are obtained at an altitude appropriate for the CAT I
approach. If not, a go-around must be performed. “
Airbus has provided adequate reference for the operator to adopt the feature of
Auto-land in CAT 1 or better visibility and left it to the Operator to carry out the
required assessment to include this capability to their operations. The Auto-land
feature provides for enhanced monitoring of the Auto-land functions and continuing
to keep visual reference throughout the landing. It proves to be an enhancement
to situational awareness when operating in inclement weather conditions.
1.18.3 Flight Plan (first Page)
28
1.18.4 Load and Trim Sheet
1.18.5 FCTM/ FCOM references
FCTM - OPERATIONAL RECOMMENDATIONS
In normal operations, the rudder should only be used during landing flare
in case of crosswind for de-crab purposes.
29
FCTM - CONSIDERATIONS ABOUT GO-AROUND
The flight crew must consider performing a go-around if the stability is not
maintained until landing or if adequate visual references are not obtained
at minima or lost below minima
FCOM - FLIGHT PARAMETERS
PM’s role of “actively monitoring” is very important: PM shall announce
“BANK BANK” when the roll angle increased above 7°.
FCOM - Ground Clearance
1.19 Useful or Effective Investigation Techniques
Nil
30
2. ANALYSIS
2.1 General
The aircraft had a valid Certificate of Registration and Certificate of Airworthiness.
All maintenance schedules, mandatory modifications and checks were carried out
as per the requirements. There were no defects / snags pending rectification, apart
from the aircraft Logo Light (unserviceable), which had no bearing on the incident.
The crew were licensed and qualified to operate the aircraft. The First Officer was
not cleared for supervised Take-off and landing for the sector. This was the crew’s
first flight for the day and they had received adequate rest and were within the
operators’ flight duty time limitations to operate the flight.
The flight Dispatch documents were prepared as per the regulatory requirements
and the crew were satisfied with the pre-flight documentations and fuel uplift. The
Load and Trim of the aircraft was as per the requirements for the flight sector.
2.2 Meteorological and Environmental Aspects
The TAF (Terminal Aerodrome Forecast) provided to the crew at the time of
departure was as below. The time of approach for the aircraft was 01:50 UTC. This
would mean the aircraft was to arrive with a forecast visibility of 800 metres in Fog
and a cloud base broken at 200 feet.
1100/1109 VRB02KT 2000 BR SCT004 SCT012
TEMPO 1100/1103 0800 FG BKN002SCT012 BECMG
1104/1105 6000 SCT012
The METARS show a rapid deterioration of the visibility right up to the point the
aircraft commenced approach. Bangalore airport, at this time of the year usually
experiences morning fog which intensifies at sunrises.
The Operations Manual Part C for Go Airlines does not cover Bangalore airport.
The phenomenon of likely rapid reduction in visibility would not be known to a
31
pilot who has not flown in these geographic regions earlier. The PF relied on the
Terminal forecast provided to him which reported marginal visibility and a low cloud
base to make an approach into Bangalore ILS 09.
The actual RVR at the time of the approach reduced very rapidly to 125 meters.
The time of the incident was just after Sunrise and the Sun was positioned at 14
degrees above the horizon and at a bearing of 112 degrees (20 degrees to the
right of the runway alignment). This would have further impacted the already
reduced visibility.
The image below illustrates the position of the sun relative to the horizon.
2.3 ATC Management in Deteriorating Weather
The Local Standby was declared at 2300 UTC of 10
th
November, when the visibility
was 2000 meters. The aircraft was informed at 01:34:31 UTC that the visibility was
200 metres and the RVR was 1500 metres. Subsequently at 01:45:13 UTC, the
visibility remained at 200 metres and RVR reduced to 1200 metres.
The Approach Controller broadcast the visibility of 200 meters and RVR of 1200
Meters at 01:45:13 UTC. The Drishti RVR recorded for this period was 125 meters
with no improvement up to the time the incident occurred. There is no
meteorological report issued by the MET department between 01:00 to 01:53 which
reports the RVR as 1200 meters. At 01:36 UTC, the Drishti software records an
RVR of 1200 meters and at 01:37 UTC the software records 800
32
meters. At 01:41 UTC, the RVR recorded was 125 meters and there was no
improvement till 01:53 UTC which is the time the incidented flight carried out the
missed approach. It appears the Approach Controller has not verified the latest
RVR from the Drishti display while making the broadcast of RVR 1200 meters. The
Approach Controller has not issued any further broadcast messages with regard
to RVR deterioration for the duration this flight was on the approach frequency.
The Display for the DRISHTI is not in clear line of sight for the Approach Controller.
This could have played a role in the controller transmitting earlier RVR.
The aircraft ahead of the incidented flight initiated a Go Around. The reason for Go
Around was not intimated to the Tower Controller and the Tower Controller handed
over the aircraft to Approach control. The incidented aircraft continued its approach
and the PIC reviewed the Go Around Manoeuvre with the First Officer and this
aircraft was given landing clearance when it was 4NM on approach. By the time the
incidented aircraft was over the threshold, the tower controller would have the latest
RVR which had reduced to 125 meters and nothing was visible from the tower.
However, this reduction was not transmitted to the aircraft.
After the incidented aircraft was on the missed approach the tower controller
transferred the aircraft to approach control. Shortly after this, another aircraft was
heard inquiring about the visibility improvement and the approach controller
informs them that the RVR is 125 meters and not improving.
The tower controller was aware of the Local Standby procedure being applicable
for that morning. The Tower has the RVR indication panel (DRISHTI) located in
the Tower along with a MET Officer stationed there. The Indication Panel reports
the RVR every 10 seconds and the sharp reduction in RVR would have been
displayed on the screen. Once the preceding aircraft carried out a missed
approach, the tower controller could have quickly viewed the DRISHTI application
for the latest RVR (which was 125 meters at the time) and transmitted the same to
the incidented aircraft.
33
A Bird Chaser who was positioned near A-8 northern shoulder reported that the
visibility was low with dense fog. The Bird Chaser heard the engines for the subject
aircraft to be louder than usual. The Bird chaser immediately reported to the shift
in-charge about the aircraft flying above him.
Location of the Bird Chaser
2.4 Flight Operations
2.4.1 Dispatch Criteria
The incidented flight was a self-dispatch flight from Nagpur to Bangalore. The crew
are to collect the flight documents and assess the fuel requirements and proceed
to the aircraft. The operational flight plan was calculated with 4100 Kg of extra fuel
due to fuel tankering. This would translate into an additional 2 hours of holding fuel
at the destination, if required. The Flight plan catered for 2 Destination alternates.
The Primary Alternate was the further alternate of Hyderabad and the secondary
alternate was the closer airport Chennai. The minimum diversion fuel was provided
for both alternates.
The visibility in the weather forecast for Chennai (the closer airport) was 1500
meters in Mist with a temporary reduction between 00:00 UTC to 03:00 UTC to 800
metres in Mild Fog. The secondary alternate which was closer by distance, would
have been at the minimum visibility required for arrival. Hyderabad which
34
was the Primary Alternate although a little further away had adequate margin for
weather and reported a visibility of 3000 metres with a temporary reduction to 1500
metres in mist between 00:00 to 03:00 UTC. Both the alternates met regulatory
requirements for dispatch.
As per the operator’s Operations Manuals, the PF is assigned the responsibility
and authority with regards to the decisions needed to be made with regards to
weather requirements and fuel for completing the flight. The Flight Dispatcher role
is that for providing support to the PF and aid in decision making. However, for the
incidented flight the flight papers were received by the PF at Nagpur airport. There
is no Dispatcher available at Nagpur for briefing. There was no verbal briefing
provided to the crew for the flight and the crew did not contact the Dispatch office
for any additional information.
The Airline also follows an Adverse Weather Watch and has listed procedures for
Flight Planning during fog. The procedures stated in these sections require the
aircraft and crew being scheduled to adverse weather stations to be upgraded to
CAT III qualified in order to avoid diversions. These procedures do not include
stations that may experience fog wherein the visibility could reduce below minima,
but do not have CAT III certification, as is the case with Bangalore.
For the incidented flight, although the forecast weather was above the regulatory
requirements for dispatch, the visibility reduced very quickly below the minimum
required for an approach. This was neither forecast in the Meteorological briefing
nor intimated by the flight dispatcher as a potential threat. The phenomenon is not
uncommon for the location given the time of day for the winter season. Guidance
to the PIC about such phenomena may have provided insight and prepared him to
expect a sharp decline in visibility.
2.4.2 Crew Perspective of the Flight
The PF stated that the layover stay was good. They carried out the Breath Analyser
test and the flight was uneventful till the approach phase in Bangalore. The First
Officer had assumed the role of PF from 1000’ to 1000’ for the sector.
35
During Approach, they were following a B737 aircraft which executed a missed
approach. At this point, the PIC reviewed the Go Around procedure. Since the First
officer had low (on type) experience, the PIC had to additionally monitor the First
Officer actions causing additional workload. The crew sighted the approach lights,
centre line and threshold lights at 600 feet on approach. At 50 feet, with the
approach lights beneath the aircraft and the sun in their eyes, the visibility was
blurred. With the Fog conditions and the sun rays in his eyes, the PIC
misinterpreted the left runway edge lights to be the runway centreline lights. He
then initiated a bank toward the left while arresting the descent rate and initiated
the flare manoeuvre. The PIC then scanned the localiser indication on the PFD
and realised the localiser pointer showed a deviation. The First Officer announced
Go Around due to loss of visual reference to the runway environment. Being
uncertain of his position and hearing the call from the First Officer, the PIC initiated
a Go Around manoeuvre.
The crew heard some aural warnings after lift-off but were unable to clearly
ascertain these. To the best of their recollection, it was a GPWS and a Stall
warning. The First Officer observed the ECAM for Engine 1 Stall during the Go
Around.
2.4.3 STOL Policy (1000’-1000’)
The PIC gave the First Officer controls from 1000’ after Take-off to 1000’ prior to
landing. The P2 was relatively new to the A320 and there was additional monitoring
on part of the PIC. The P1 was not aware of the company policy with regards to
Enroute flying for the P2. The Airline does not permit 1000’ to 1000’ flying. During
routine CVR monitoring, the Safety Department had not raised any observations
with regards to the 1000’ to 1000’ flying.
2.4.4 Airbus 320 Auto-land Capability in CAT 1
As per the Airbus 320 Flight Crew Technique Manual, the crew are advised to plan
the approach using the best approach capability available. This is normally the
CAT 3 DUAL with Auto-land depending on the aircraft status. The crew then
36
assess the weather and plan a possible downgrade capability if applicable. For
Bangalore Runway 09, the approach category is CAT 1 ILS and the aircraft was
flown down to CAT 1 ILS minimum Altitude to sight the runway and could continue
for either a manual or automatic landing (Auto Land).
Airbus has provided adequate reference for the operator to adopt the feature of
Auto-land in CAT 1 or better visibility and left it to the Operator to carry out the
required risk assessment to include this capability to their operations. The Auto-
land feature generally provides for enhanced monitoring of the Auto-land functions
and continuing to keep visual reference throughout the landing. If used through
adequate training and detailed procedures it proves to be an enhancement to
situational awareness when operating in inclement weather conditions.
In this incident, if the provision for carrying out an Auto-land was made available,
the crew would have 3 possible scenarios.
1. Runway in sight with the aircraft trajectory along the intended path: An Auto-
land being made keeping the runway environment in sight would reduce
pilot workload of manual flying and would increase the monitoring of flight
path.
2. Runway in sight with the aircraft trajectory not along the intended path: The
crew would carry out a missed approach as laid down by procedure.
3. Runway not in sight: The crew would carry out a missed approach.
Although the Auto-land for CAT I ILS provision is available for the A320 aircraft,
each operator must carry out a safety risk assessment prior to carrying out the
Auto-land feature and assess and mitigate the risks derived from such an
exercise.
2.5 Aircraft Handling
2.5.1 Visual Perception
The crew of the aircraft were provided with weather conditions which were above
the minimum required to commence approach and landing. While the actual
37
visibility began to reduce to 125 meters in a very short period of time, the crew were
not informed of the same. The crew expected to have adequate visual reference
approaching minimums to establish contact with the runway environment and
continued to make a manual landing. The crew sighted the approach lights above
the decision altitude. This sighting was due to the illuminated Approach Lights,
however, as the aircraft approached 100’ Radio altimeter, the approach lights
would have passed under them and the remaining runway lighting were inadequate
to maintain runway environment reference. The lack of centreline lights would have
contributed toward the loss of visual reference. This situation would have been
further aggravated with the position of the sun just 14° above the horizon and at
112° which is about 20° to the aircraft’s right. The glare would have possibly
reduced the visibility toward the right of the aircraft and the only remaining linear
lighting visible to the PIC was the runway edge lights to the left. Given the fact that
there was only one linear light visible, the PIC assumed that to be the runway centre
line lights (which the aerodrome did not have installed). At 110’ Radio Altitude, the
PIC began an attempt to align the aircraft with the runway edge lights and while
doing so, arrested the descent rate significantly.
The images below are replicated using visuals from a flight simulator. It is
pertinent to note that the visuals in flight simulators would not be as accurate
as the crew experienced from the flight deck due to the simulator limitations.
The simulator would not be able to accurately factor the position of the sun
with reference to the aircraft and also the degree of fog and its refractive
index. However, the images have been used to aid the reader in
understanding the general variation between what was expected vs. what
the crew saw (on approximation)
38
200 feet Altitude and 1200 meters visibility
100 Feet altitude and 500 metres visibility
39
50 feet Altitude and 125 meters visibility
2.5.2 Aircraft Handling Till Touch Down
The aircraft was flown on Autopilot down to 220’ RA. The aircraft was stabilized on
approach as per the company’s stabilized approach criteria at 1500’. The Autopilot
and auto thrust maintained the ILS profile with no deviations and the Auto Thrust
was in speed mode for the Approach speed selected.
The call “Approach Lights” was called by the First Officer at 350’ RA. The Autopilot
was disconnected at 220’ RA by the PIC and at 110’ a slight bank was initiated
toward the left. The bank angle gradually increased to10 degrees and the pitch was
increased to arrest descent.
The Auto-thrust remained in speed mode and maintained the required thrust to
maintain speed. At 25’ RA, the aircraft was maintaining altitude and the Auto-thrust
was retarded to idle. This caused the Auto-thrust to disconnect and maintained idle
thrust. Following this, the PIC continued to maintain the altitude while attempting
to align with the left runway edge light assuming these to be the centre line lights.
40
The PIC used alternating roll inputs along with rudder inputs that are indicative to
an alignment attempt by the PIC. As the aircraft bank to the left was increased, the
localizer deviation was also increasing and reached 3.5 units deviation prior to touch
down. The First Officer did not make any call out for the lateral deviation.
The First Officer announced Go Around 2 seconds prior to the aircraft contacting
the unpaved surface. The Go Around thrust was initiated by the PIC immediately
and a pitch up command was recorded by the left side stick. However, the aircraft
was below final approach speed and the response to the pitch command did not
result in a climb and the aircraft contacted the unpaved surface. After touch down
on the main wheels, there is several pitch and roll commands registered on both
side-sticks up to the point the aircraft lifted off the surface.
Flare and go-around / longitudinal axis
41
The plot above shows the crew side stick and rudder pedal inputs along the
longitudinal axis.
Bank Angle variations prior to and after touchdown
No.
Time
Roll
RA
Comment
1
01:51:55
L 1.5
102
A gradual bank of 1.5 degrees left is developed
2
01:52:02
L 2.1
29
Flare Law is active
3
01:52:08
L 9.8
24
Maximum Bank of 9.8 degrees prior to Touch down
4
01:52:12
L 5.0
18
Extended flare from 29’ – 18’ for 10 seconds. Bank
angle reducing
5
01:52:15
L 0.3
0
Touchdown on main landing gear
6
01:52:19
R 17.0
4
Aircraft banks aggressively to the right and gets
airborne again
The aircraft begins a gradual bank toward the left after autopilot is disconnected.
The PIC then reduces the descent rate (flying almost level) while increasing left
bank to align with the left runway edge lights (which he believes are the center line
lights). At the point of touchdown, the wings are near level. During the 5 seconds
the aircraft has touched down, the PIC initiates an aggressive right bank which
reaches 12 degrees. It reaches 17 degrees just after lift-off. The key points of FDR
analysis are shown on the figure below (from OEM report)
400
600
500
300
200
100
0
Radio Altitude / Roll
1:51:25
1:51:27
1:51:29
1:51:31
1:51:33
1:51:35
1:51:37
1:51:39
1:51:41
1:51:43
1:51:45
1:51:47
1:51:49
1:51:51
1:51:53
1:51:55
1:51:57
1:51:59
1:52:01
1:52:03
1:52:05
1:52:07
1:52:09
1:52:11
1:52:13
1:52:15
1:52:17
1:52:19
1:52:21
1:52:23
1:52:25
1:52:27
1:52:29
1:52:31
1:52:33
1:52:35
1:52:37
Radio Altitude ROLL Angle
-10
-15
5
0
-5
25
20
15
10
42
UN RA
MS SA
GS 'Mkt CAS 17111 CAS 12
.
1•1 CAS
ON GOMM
POI L
MOSS
.1511
.
WS asimenon
MOMS 51 STALL
CAS 1.161.1 CAS 13710
/MOWS 11A110120 ST ME Cut
LC CONS S
JAR SOS SA
CA
COTIIINUOUS LEFT WINO 1131,11
AND f 00.0
.
.0U. 0.0131.
tin X1130/91 MAL ORDIETS
I ______
WSW 41.-k
KILO 1131.1.
RAW PROXPI MUM. CSIDETtS
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,
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.171m
-
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/
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33
I
-- 1.
111471.:71..0:•••
-ISO.
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,
A
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211
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013734
NOT TO SCALE
AC N CLOW
I VI 133.1
1 3 1 1 2 1 1 1 1 } G R A
54 RA
44C 'LOAM" MOM maw raft...auto issecosos
us sea CAS ISOM .7t.t I CAS "Sat
11110) 01.3313
CA.3
.
. . . . . . . . . . . . .
All
out of runway
140.301" MOM'
Stitt/
fa COIF
SUSI OLL
43
The figure above highlights the clearance margin from body contact
Airbus has given the clearance margins to avoid aircraft body contacting the
ground (Body pitch up v/s body roll angle). As per this, with main landing gear
fully extended and a pitch angle of +13.5°, the right aircraft aileron will contact
the ground when the roll angle reaches +15.7°. In the present case, due to nose-
up and right roll orders applied by the flight crew when the aircraft was on ground,
pitch and right roll angles increased and reached high values close to the ground
clearance diagram limits. The right aileron was close to the ground at lift off.
44
2.5.3 Aircraft Handling after Touch Down and Lift Off
The touchdown and subsequent landing roll was bumpy. The
accelerometers recorded high values in the lateral and vertical plane. This
confirms that the aircraft had contacted and rolled on an undulating surface.
The Aircraft lifts off with a high bank angle to the right which increased to
18° one second after lift-off. After lift-off, the crew received three warnings
within 15 seconds.
Time delay*
Warning
Remarks
1
2 seconds
Terrain warning
The EGPWS sensed an
obstacle
2
6 Seconds
Low Speed Warning
The aircraft detected
the speed is low
3
4 Seconds
Engine 1 Stall
(ECAM)
The EWD displayed
and Engine stall
* time delay between events.
The stimulus for the crew was high following a perceived hard landing on the
runway during a Go Around manoeuvre.
The First Officer identified the ECAM message and alerted the PIC. Once the PIC
had established a climb, the ECAM actions were taken. The PIC retarded the
Number 1 thrust lever to idle and the Stall conditions stopped and the ECAM
actions were completed. The crew waited for 230 seconds after retarding the thrust
levers and on observing normal parameters increased the thrust levers slowly in
an attempt to restore the engine. The engine parameters were symmetrical and
produced the commanded thrust of 64% N1. After 6 seconds, the Master Caution
for ENG 1 Stall triggered and the crew reduced the thrust levers to idle. The thrust
levers were kept at idle for the rest of the flight.
2.5.4. Decision Making and Diversion
Any decision making model requires the ascertaining of the facts of the current
situation. Some pertinent facts were not considered by the crew as they were
probably unaware of them at the time. The crew did not discuss the touchdown
location after the Go Around was initiated assuming it to be a hard landing on the
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runway. The crew did not inform the ATC about the engine stall and only advised
the ATC of a technical problem.
The crew initially held for completion of abnormal procedures and attempted a
restoration of engine while waiting for any improvement in visibility in Bangalore.
The crew eventually diverted to Hyderabad VOHS airport after assessing the
weather.
2.6 Factors Leading to the Incident
When the aircraft was radar vectored for an ILS 09 approach in VOBL, the ATC
advised all aircraft that the visibility was 200 meters and the RVR was 1200 meters.
There was no further update on meteorological conditions provided to the crew.
The preceding aircraft to the incidented flight also carried out a missed approach
while on ILS 09. The Tower Controller has neither asked the reason for the Go
Around of the preceding aircraft nor updated the current RVR. The First Officer
sighted the Approach Lights for runway 09 at 100’ above the Decision Altitude. The
autopilot was disconnected passing decision altitude and the PIC took manual
control (now PF) of the aircraft.
Once the aircraft crossed over the approach lights segment, due to the prevailing
visibility which was much lower than expected, the PF lost visual reference to the
runway environment. In addition, the orientation of aircraft was in line (opposite) to
the reflection from the sun and as such the PF could only see the left runway edge
lights (for approximately 150 meters ahead). Assuming the left runway edge lights
to be the centreline lights, the PF manoeuvred the aircraft with a left bank to align
with the left runway edge. The PM did not make any callout for Localiser deviation
as a result of the manoeuvre.
The PF arrested the descent rate to allow for more time to align for landing. The
thrust levers were retarded once the automated “retard” call was generated at 30’
radio altitude. The rudder and side stick deflections (DFDR) were indicative of the
attempt to align the aircraft with the left runway edge lights.
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Actual scenario at this point of time was that the crew expected the visibility to be
higher than what they experienced at decision height. Sighting of the approach
lights provided confirmation to the crew that they had established the required
visual reference to continue for a manual landing. However, as the aircraft flew
over the approach lights the remaining runway lighting was inadequate to keep
visual reference. The PF then sighted the runway edge lights and assumed these
to be the centreline lights not realising that the airport does not have centre line
lights. The PF then manoeuvred to align with the left runway edge lights. The low
visibility and the relative position of the sun might have contributed to the PF
perceiving the left runway edge lights as centre line lights. The aircraft contacted
the unpaved surface after having initiated a Go Around.
2 seconds prior to the main gears contacting the surface, the PM announced “Go
Around” and the Go Around actions were immediately carried out by the PF.
Both aircraft main landing gears contacted the unpaved surface with the Left Main
Gear contact occurring 01 second prior to the Right Main Gear. The pitch attitude
at touchdown and subsequent side stick input prevented the nose wheel from
contacting the surface. High accelerations were recorded in the vertical axis of upto
1.8g and in the lateral axis of -0.55g. The aircraft became airborne after 5 seconds
of rolling on the undulating surface with a bank angle of 18 degrees to the right just
after getting airborne. The Flight Data records a terrain warning followed by a low
speed warning a few seconds after lift-off. Once the aircraft is established in climb
with the wings level, an ECAM alert for Engine 1 Stall is recorded and the crew
follow the required actions for the ECAM. The visibility at VOBL is now reported at
125 meters with no improving trend. The crew attempts to restore the number 1
engine by advancing the thrust levers however, an engine stall alert occurs and
the thrust lever for engine 1 is retarded to idle and left at idle for the remainder of
the flight.
The crew discussed a diversion to Chennai and Hyderabad. The decision is made
to divert to Hyderabad airport since the visibility was higher than that at Chennai
with no reducing trend. The aircraft landed safely in Hyderabad.
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3 CONCLUSION
3.1 Findings
3.1.1 The aircraft had a valid Certificate of Registration and Certificate of
Airworthiness.
3.1.2 All maintenance schedules, mandatory modifications and checks were carried
out as per the requirements. There were no defects / snags pending
rectification.
3.1.3 Flight crew were appropriately licensed to undertake the flight. Their medical was
valid and both had undergone pre-flight medical checks including BA test which
was negative.
3.1.4 The Airline has laid down procedures for Flight Planning during Fog. The
documented procedure refers to monitoring the TAF and planning the crew with
the CAT III qualifications. The airline does not cater for FOG for stations that do
not have CAT III ILS approach facilities.
3.1.5 The Flight was self-dispatched by the crew. There was no contact with the
dispatch office for any additional information. The Pre-flight documents met the
company and regulatory standards.
3.1.6 The First Officer was the Pilot Flying from 1000’ after Take Off to 1000’ prior to
landing. The landing checklist was carried out by the PIC as PM. The operator
does not have a documented procedure for this practice. Task switching at a late
stage of flight with the prevailing visibility, reduced the situational awareness of
both pilots.
3.1.7 The ATC for Approach and Tower have the DRISHTI RVR indication available at
the controller stations. Neither controller informed the aircraft of the rapidly
reducing RVR.
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The Approach Controller made a broadcast for RVR which was 8 minutes old as
recorded by the DRISHTI software. The DRISHTI Display is not in clear line of
sight from the approach controller station.
The Tower Controller did not inform the reducing trend of the RVR to the
incidented aircraft even after the preceding aircraft had carried out a missed
approach.
The DRISHTI indicating panel does not have aural or visual alerts for sudden
RVR deterioration below threshold values.
3.1.8 After the preceding aircraft carried out a missed approach, the go around
procedure and actions required on the part of PF and PM were discussed from a
crew coordination perspective. The crew could have obtained the latest RVR
observation from ATC at this point for better situational awareness.
3.1.9 The Aircraft was stabilised on approach as per the operator’s requirements and
both autopilots were selected for the ILS.
3.1.10 At 220 feet Radio Altitude, the autopilot was disconnected and the PIC
continued on the ILS profile to 110 feet Radio Altitude. The PIC then
manoeuvred the aircraft by initiating a left bank and reducing the rate of
descend to be on the runway perceiving the left runway edge lights as the
centre line lights.
3.1.11 At 27 feet Radio Altitude, the thrust was retarded to Idle after the automatic call
out for “Retard”. This disconnected the Auto Thrust system and the aircraft speed
began to reduce as the rate of descent was being maintained near level by the
PIC side stick pitch command.
3.1.12 2 seconds prior to touchdown the First Officer announced “Go Around” and the
PIC initiated the Go Around manoeuvre.
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3.1.13 The aircraft contacted the unpaved (kutcha) surface by the side of the runway
with the left main landing gear making contact 1 second prior to the right main
landing gear.
3.1.14 Due to the undulating terrain, there were excessive vertical and lateral loads. Due
to these loads experienced and a combination of side stick inputs, the aircraft
was airborne with a bank angle of 18°.
3.1.15 There was ingestion into the engines during the ground roll and a subsequent
engine stall condition developed for the number 1 engine.
3.1.16 The crew informed the ATC that they had a technical problem after Go Around.
The crew carried out a hold for a few minutes and after observing no
improvement in visibility, the crew elected to divert to Hyderabad.
3.1.17 The Airline has oversight procedures for routine CVR monitoring and landing
below minima events. The 1000’ to 1000’ flying was not picked up during routine
CVR monitoring and there were no records of below minima landings.
3.1.18 At the time of occurrence, the organization was not having an active flight watch/
monitoring programme. Once the aircraft departed, no advice or update was
provided to the flight crew. The investigation has observed the above aspects in
other organizations also.
3.2 Probable Cause
•
The incident occurred due to loss of visual reference after crossing the
approach lights resulting in aircraft getting offset from the runway and
landing gear touching the kutcha during late Go Around.
•
The PIC who was the pilot flying, in an attempt to regain the visual reference
sighted the left runway edge lights and assuming these to be centre line
runway lights manoeuvred the aircraft to the left in an attempt to make an
alignment late in the landing phase.
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•
The far lower visibility than anticipated by the crew, along with the sighting
of approach lights and relative position of the sun in the early morning hours
misled the visual perception of the Pilot Flying.
•
The update of rapidly reducing RVR not made available to the flight crew.
•
Loss of visual reference after crossing the Approach Lights.
•
Flight crew not initiating a timely Go Around
•
PIC giving flying to the First Officer and not taking over controls at an early
stage prior to the landing.
•
The OEM has a provision for Auto-land capability in visibility conditions
higher than CAT I ILS. The Airline has not carried out a safety assessment
for implementing this capability in their procedures. Having the procedures
laid out for Auto-land, the crew would have benefitted with a higher degree
of situational awareness while optimising the use of automation.
4.0 SAFETY RECOMMENDATIONS
4.1 All airline operators must emphasize during simulator training that the crew
correctly assesses any reduction in visibility having occurred below minimum
requirements while on approach and the corrective actions thereon. This training
should include adequacy of remaining visual reference and must focus on crew
assessment and response to the same.
4.2 All airline operators may assess the inclusion of the OEM provision for carrying out
an Auto-land in CAT I or higher visibility. This must be done after carrying out a
Safety Risk Assessment.
4.3 All airline operators may expand the Fog Watch to include stations which are likely
to have marginal visibility during winter (fog months) irrespective of the Aerodrome
with CAT II or lower facilities.
4.4 The Flight Safety Department of Go Air should enhance oversight in order to
capture deviations from Standard Operating Procedures such as but not limited to
the 1000’ to 1000’ flying by the First Officer as Pilot Flying.
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4.5 AAI and IMD must ensure that the software display providing real time visibility /
RVR are located in clear sight of the Air Traffic Controller for all stations.
4.6 IMD may carry out an evaluation for inclusion of Audio / Visual Alerts from the
software being used for updating of RVR/ Visibility, whenever Visibility / RVR
reduces below threshold values.
4.7 DGCA should extend, the Adverse weather watch system/ procedure for other
seasonal variations wherein operating conditions deteriorates significantly like
monsoon operations.
4.8 DGCA should positively provide closure report as per the time limits on the audit
findings after receiving the Action Taken Reports from the Operator.
-S/d-
(R S Passi)
Investigator-In-Charge
-S/d-
(Kunj Lata)
Investigator
-S/d-
(Capt. Gaurav Pathak)
Investigator
Date: 30.09.2020
Place: New Delhi
