Final Investigation Report on Serious Incident to
M/s Jet Airways (India) Ltd. B-737-800 Aircraft
VT-JGE on 14-01-2015 at Kolkata Airport
COMMITTEE OF INQUIRY VT-JGE
(N S Dagar )
Jt. GM (ATM), AAI
Member, COI – VT- JGE
(Amit Gupta)
Director (AED)
O/o Dy. DGCA, Bengaluru.
Chairman COI – VT- JGE
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 2012, the sole objective of the investigation
of an accident shall be the prevention of accidents and not apportion blame
or liability.
This document has been prepared based upon the evidences collected during
the investigation, opinion obtained from the experts and laboratory
examination of various components. Consequently, the use of this report for
any purpose other than for the prevention of future accidents could lead to
erroneous interpretations.
INDEX
CONTENTS PAGE No.
SUMMARY
2
1 FACTUAL INFORMATION
3
1.1 HISTORY OF THE FLIGHT
3
1.2 INJURIES TO PERSONS
3
1.3 DAMAGE TO AIRCRAFT
4
1.4 OTHER DAMAGE
4
1.5 PERSONNEL INFORMATION
4
1.6 AIRCRAFT INFORMATION
6
1.7 METEOROLOGICAL INFORMATION
8
1.8 AIDS TO NAVIGATION
8
1.9 COMMUNICATIONS
9
1.10 AERODROME INFORMATION
9
1.11 FLIGHT RECORDERS
9
1.12 WRECKAGE AND IMPACT INFORMATION
11
1.13 MEDICAL AND PATHOLOGICAL INFORMATION
11
1.14 FIRE
11
1.15 SURVIVAL ASPECTS
12
1.16 TESTS AND RESEARCH
12
1.17 ORGANISATIONAL &
MANAGEMENT INFORMATION
12
1.18 ADDITIONAL INFORMATION
12
1.19 USEFUL AND EFFECTIVE TECHNIQUES
20
2 ANALYSIS
21
2.1 SERVICEABILITY OF AIRCRAFT
21
2.2 WEATHER
21
2.3 ANALYSIS OF FLIGHT DATA RECORDERS
21
2.4
PILOT FACTOR
22
2.5 CIRCUMSTANCES LEADING TO INCIDENT
22
3 CONCLUSIONS
23
3.1 FINDINGS
23
3.2 PROBABLE CAUSE OF THE SERIOUS INCIDENT
24
4 SAFETY RECOMMENDATIONS
24
APPENDICES
1
FINAL INVESTIGATION REPORT ON SERIOUS INCIDENT TO
M/s JET AIRWAYS (INDIA) LTD. BOEING B 737-800 AIRCRAFT
VT-JGE AT KOLKATTA AIRPORT ON 14-01-2015
(All timings in the report is in UTC)
1. Aircraft Type Boeing 737-800
Nationality
Indian
Registration VT-JGE
2. Owner Celestial Aviation Trading 1 Ltd., Ireland
3. Lessor GECAS Technical Services Ltd., Ireland
4. Operator M/s Jet Airways (India) Ltd., Mumbai
5.
ALTP Holder
NIL
6. Co- Pilot CPL Holder
Extent of injuries NIL
7. Date & Time of Serious
Incident
14-01-2015; 0340 UTC
8. Place of Serious Incident Runway 19L, NSCBI Airport, Kolkata
9. Last point of Departure CSIA Airport, Mumbai
10.
Intended landing place NSCBI Airport, Kolkata
11.
No. of Passengers on board 144
Extent of injuries NIL
12.
Type of Operation Scheduled Passenger Flight
13.
Phase of Operation landing
14.
Type of Serious Incident Tail Strike
15.
Co-ordinates of Accident Site Lat 22° 40 ' 13" N, Long 88° 26' 58 " E
AMSL 23 feet
2
SUMMARY:
On 14
th
January 2015, M/s Jet Airways Boeing 737-800 aircraft VT-JGE was involved
in a serious incident at Kolkata Airport. The aircraft was scheduled to operate flight
number 9W615 from Mumbai – Kolkata- Bagdogra. While carrying out landing at
Kolkata airport, aircraft suffered tail strike. The aircraft was under command of PIC
having ATPL and Co-pilot CPL. There were 144 passengers, 06 Cabin crew and 02 ACM
on board the aircraft.
The aircraft took off from Mumbai at 0141UTC and the flight from Mumbai to Kolkata
was uneventful till touchdown. Visibility at the time of landing was 800 m and ATC
assigned Runway 19 L. PIC decided to carry out dual auto pilot approach with the
intention of carrying out a manual landing.During landing at 0340 UTC aircraft touched
down with a pitch of 5.1 ° and speed V
ref
-10 kts. The flare lasted for about 14 seconds
and the aircraft pitch reaches 9.14°. The fuselage and tail skid contacted the Runway.
During the post flight walk around inspection by the AME, damages were noticed to tail
skid and scrapping of aft belly of the aircraft. There was no fire or injury to person on
board the aircraft.
Ministry of Civil Aviation vide order No. AV 15018/150/2015-DG dated September
2015 constituted a committee of inquiry to investigate the cause of the Serious Incident
under Rule 11 (1) of Aircraft (Investigation of Accidents and Incidents), Rules 2012.
The committee consist of Sh. Amit Gupta Deputy Director-AED, DGCA as Chairman
and Mr. N S Dagar Jt. GM (ATM), AAI as member.
The probable cause of Serious Incident is due to “decrease of airspeed below V
ref
during
landing process and increase in pitch attitude resulted into the Tail Strike.”
3
1. FACTUAL INFORMATION.
1.1 History of flight
On 14
th
January 2015, M/s Jet Airways Boeing 737-800 VT-JGE was scheduled to
operate flight number 9W615 from Mumbai – Kolkata- Bagdogra. The crew consisting
of a PIC having ALTP & Co-pilot CPL and 06 Cabin crew. It was the first day of a work
cycle for the pilots. There were 144 passengers (139 Adults + 3Child + 02 Infants) and
02 ACM on board the aircraft.
The aircraft took off from Mumbai at 0141UTC and the flight from Mumbai to Kolkata
was uneventful till touchdown. The approach was normal and PIC at 6000 feet
requested ATC (approach) for high speed descend. ATC allowed high speed descend
and assigned Runway 19 L for landing. Landing Flaps were selected as 30
°
. However,
there was discussion by PIC with co-pilot regarding Flap position to 40°. Visibility at
the time of landing was 800 m and the crew decided to carry out dual auto pilot
approach with the intention of carrying out a manual landing. V approach was 153 kts
& V ref was 148 kts. The landing was carried out by PIC and co-pilot was monitoring
the instruments. During landing at 0340 UTC aircraft touched down with a pitch of
5.1° and speed V
ref
-10 kts. The Flare lasted for about 14 seconds (from 30 ft to MLG
touchdown) and the aircraft pitch reached 9.14°. Aft fuselage and Tail Skid contacted
the Runway. G recorded during touchdown was 1.36. On landing the aircraft taxied to
the bay
on its own power. Passengers and crew disembark from the aircraft normally.
During the post flight walk around inspection by the AME, damages were noticed to
tail skid and aft belly of the aircraft. There was no fire or any injury to person on board
the aircraft.
1.2 Injuries to persons.
Injuries Crew Passengers Others
Fatal NIL NIL NIL
Serious NIL NIL NIL
Minor
NIL
NIL
NIL
None
2+6+2
144
NIL
4
1.3 Damage to aircraft.
The aircraft sustained minor damage. Following main damages occurred to the
aircraft.
1) Tail skid shoe rubbed but four dimples visible. Tail skid green decal was
slightly visible
2) Rubbed mark of approx. 70" long found on fuselage bottom side between
STA 867 & STA 967 and between Stringer 27 L & 27 R.
3) Rubbed mark at Frame 1016 (from 18" forward FR1016 to 18" aft of FR
1016).
4) Paint peeled off and 2 deep longitudinal gauges of approximately 9"length
ahead of FR 1016.
5) Tail Skid Cartridge core assembly damaged (shortened by 0.5").
6) 07 Rivets sheared off at STA 967 and between Stringer 27L & 27 R.
7) Shear Tie at STN 887 cracked between Stringer 27L & 27 R
8) Stringer clip at STA 907 and STA 887 at Stringer 27L bend.
9) Deep Gauges of Length 44.5" between STA 867 and STA 927 Stringer 27
L & 27 R.
10) Bulge of fuselage skin of 3.5" aft edge of frame STA 867 between Stringer
27 L & 27 R.
1.4 Other damage: NIL
1.5 Personnel information:
1.5.1 Pilot – in – Command:
Age 33 Years
License ATPL
Date of Joining Jet Airways
Jan 2008
Date of Issue/Renewal 29-07-2013
Valid up to 28-07-2015
Type endorsement B-737-700/800/900
Endorsement as PIC
08-04-2013
Date of Medical Examination 12-09-2014
Medical Examination valid upto 11-09-2015
FRTO License issue
26-09-2012
FRTO License valid upto 25-09-2017
IR Test Done 30-10-2014
IR Test Due 29-10-2015
5
Total Flying Experience 5248:10 hrs
Total Flying Experience as P1 on Type
1583:24 hrs
Total Flying Experience as P2 on Type 3391:58 hrs
Total Flying Experience during last 01 year 973:23 hrs
Total Flying Experience during 90 days 204:17 hrs
Total Flying Experience during 30 days
62:02 hrs
Total Flying Experience during 07 days
14:23 hrs
Total Flying Experience during 24 hours 00:00 hrs
Rest period prior to duty flight 48 hrs.
1.5.2 Co-Pilot:
Age 43 Years
License
CPL
Date of Issue/Renewal 18-12-1998
Valid up to 16-05-2016
Date of Joining Jet Airways July 2006
Type Endorsement B 737-800
Date of Endorsement as Co-pilot 12-09-2007
Date of Medical Examination 27-11-2014
Medical Examination valid upto
26-05-2015
FRTO License issue 03-02-2011
FRTO License valid upto 02-02-2016
IR Test Done 17-11-2014
IR Test Due
16-11-2015
Total Flying Experience 4932:46 hrs
Total Flying Experience as P2 on Type 4557:00 hrs
Total Flying Experience during last 01 Year
597:14 hrs
Total Flying Experience during 90 days
94:42 hrs
Total Flying Experience during 30 days 40:06 hrs
Total Flying Experience during 07 days 12:17 hrs
Total Flying Experience during 24 hours
00:00 hrs
Rest period prior to duty flight 48 hrs.
6
1.6 Aircraft Information
1.6.1 General Description:
Boeing 737-800 is a Twin engine aircraft fitted with CFM 56-7B Engine. The aircraft is
certified in Normal category, for day and night operation under VFR & IFR. The maximum
operating altitude is 41000 feet. Aircraft length is 39.472 meters, wingspan is 35.8 meters
and height of this aircraft is 12.459 meters. This airplane is certified in the Transport
Category, FAR Part 25 and Part 36.
The airframe structure is fabricated in general, of high-strength aluminum alloys. Steel,
titanium and other approved materials are also used. Aluminum alloy sheet stocks are clad
for gages less than 0.063 inch thick. The fuselage is a semi-monocoque structure with zee-
type frames and skin stiffened with hat-type stiffeners. The fuselage skin panels are made
of longitudinal stiffeners mechanically fastened to sheets. Circumferential tear straps and
doublers are used where necessary. A nacelle encloses each engine. A strut attached to the
wing holds the engine and nacelle. A firewall made of corrosion-resistant steel and titanium
alloy isolates each nacelle from its strut.
The wing is made into one piece which extends through the fuselage. The wing to body
attachment is permanent. The primary wing structure is an aluminum alloy skin stiffened
by stringers made of extruded aluminum alloy. The spars primarily carry the shear loads.
The skin and stringers carry most of the bending loads. The wing is also an integral fuel
tank. The trailing edge ribs are made of aluminum alloy. The upper surface is made of an
aluminum alloy skin and reinforced honeycomb sandwich of fiberglass and graphite. The
lower surface is made of an aluminum alloy skin with a reinforced honeycomb sandwich
of aramid/graphite and fiber glass/graphite. There is access to inside of the trailing edge
for inspection, maintenance, and repair. The fixed structure of the leading edge is made of
aluminum alloy, fiberglass, or composite fiber glass and aramid, as necessary. Upward
sweeping winglets are an optional and are installed for each wing tip. These winglets
enhance airplane performance for some operations. The winglets are removable. Provisions
are retained for the installation of the standard wing tips. The wing tip uses the same
mounting provisions as the winglets. The total wing span including the winglets is 35.8
meters and the distance from centerline to wing tip is 17.9 meters. Winglets are installed
in VT-JGE aircraft.
7
1.6.2 Aircraft Technical Information
1. Manufacturer Boeing Commercial Airplane Group ,
USA
2. Type B 737-800
3. Aircraft Registration VT-JGE
4. Constructor Sl. No. 32663
5. Year of Manufacturer 2004
6. Certificate of Registration No. 3200/2
7. Certificate of Registration valid upto 21-11-2016
8. Certificate of Airworthiness No. 2609
9. C of A renewed on 27-11-2014
10. C of A valid up to 26-11-2016
11. ARC issued on 27-11-2014
12. ARC valid up to 26-11-2015
13. Category of C of A Normal
14. Subdivision category of C of A Passenger/ Mail/Goods
15. Total Number of Seats VT-JGE 16 Premier +138 Economy
16. Minimum Crew Two
17. Maximum AUW 79015 Kgs
18. Total Aircraft Hours 38078
19. Total Aircraft Cycles 16650
20. Engine Manufacturer CFM
21. Engine Type CFM 56 -7BM24
22. Maximum Engine Thrust 26000 Lbs.
23. Last Layover Inspection on 13-01-2015 at Mumbai
24. Last Layover Inspection on 38069:54 Hrs, CSN 16643
Manual Load & Trim sheet was made for the flight. The Details of basic weight schedule
were as follows:-
Weight Maximum Permissible (Kgs)
Actual Weight (Kgs)
Take-off weight 79,015 71,034
Landing weight
66,360
65,526
Zero Fuel weight
62,731
58,986
To facilitate the calculation of the position of the center of gravity (CG), the passenger
cabin is divided into six sections, 0A, 0B, 0C, 0D, 0E, 0F.
8
Zone Row No. Max Capacity Actual Seating
0A
1-2
8
5
0B 3-4 8 1
0C 10-16 36 35
0D 17-22 36 35
0E
23-28
36
36
0F
29-33
30
30
However, the division between the sections was not visibly apparent in the cabin.
The Boeing 737 has two lower cargo compartments for Baggage & Cargo. A forward cargo
compartment, which is divided in hold #1 and hold #2 and an aft cargo compartment
consisting of hold #3 and hold #4.
Cargo Hold
Maximum Capacity (Kgs)
Actual (Kgs)
1 888 400
2 2670 1571
3
3467
1950
4 570 400
The Middle Aerodynamic Chord (MACTOW) was calculated as 29% and Stabilizer trim
for takeoff was calculated as 4.60 °s.
Dry Operating weight for the flight was 43943 Kgs. Fuel available was 12048 Kgs.
CG was within the prescribed limit during takeoff and landing.
1.7 Meteorological information:
Weather at 0320 UTC was visibility 900 meters, runway 19L RVR 1200m, MID 1000m
winds 360/5kts. , Temperature 17°, QNH 1018 hPa and Dew point 15 °.
Weather at 0350 UTC was visibility 900 meters, runway 19L RVR 1400m, MID 1100m
and winds 340/5kts Temperature 17°, QNH 1018 hPa and Dew point 15 °.
At the time of approach 0336 UTC, ATC reported visibility of 800 meters, runway 19L
RVR 1200m, MID 1000m, winds 350/05kts.
1.8 Aids to navigation:
Kolkata airport is equipped with VOR / DME (frequency 112.50 MHz) and NDB
(frequencies 385 KHz & 404 KHz). PAPI & ILS Cat- II is installed on Runway 19L. ILS
Cat-I is at 01R & SAPL at 01L.
9
1.9 Communications:
The aircraft was in contact with Kolkata ATC on frequency 118.1 MHz. From the tape
transcript it was evident that there was no communication problem between the Flight Crew
& ATC from initial contact till stopping the aircraft.
The Communication frequencies for Tower are 118.1 MHz, Approach is 127.9 MHz, SMC
Controller 121.9MHz, Kolkata Radar 127.9 M Hz, and ATIS Broadcast is at 126.4 M Hz.
Tape transcript of SMC Controller 121.9MHz and Pilot have been analyzed. Perusal of
Transcript reveals that PIC requested for high Speed descend from 6000 feet to 3000 feet
which was approved.
1.10 Aerodrome information.
Netaji Subhas Chandra Bose International (NSCBI) Airport ( IATA code: CCU, ICAO:
code VECC) is an international airport located in Kolkata, West Bengal . The elevation
AMSL of airport is 7.2M (23 FT) and reference temperature is 36°C. The airport is licensed
by DGCA for both IFR and VFR traffic. The airport reference code is 4E. The airport has
two parallel runways made of Asphalt.
01L/19R, 3,270 m × 45 m
01R/19L, 3,628 m × 45 m
The Airport Reference point is 223914.2N, 0882648.18E. Runway has marking for
Designation, THR, TDZ, Centreline, Rwy Edge and is lighted for THR, Edge, End, TDZ,
and Centreline. The Airport Rescue and Fire Fighting Services is Category ‘9’ (Nine).
Apron has parking capacity of 01 code F, 16 code E, 6 code D and 36 code C aircraft
respectively.
1.11 Flight recorders.
The aircraft is fitted with Solid State CVR & DFDR. The CVR & DFDR was removed
from the aircraft after the incident & data from both CVR & DFDR were downloaded and
analyzed after the incident. A full analysis was carried out for the approach and landing
phases of the flight. Salient observations made from the CVR tape transcript are given
below:
10
Station Relative Time
(Hr: Min: Sec)
Transcript
P1 1:20:56 Dual Autopilot
P2 1:20:56 Checked
P1 1:21:46 Flaps 40 Karnaa Chahiye thaa
P2 1:22:13 500" stabilised
P1 1:22:14 checked
P2 1:22:22 Runway Visuals
P1
1:22:23
Okay field visual
NOISE 1:22:24 Stab trim trimming noise
Audio 1:22:26 Minimums
P1 1:22:31 Visual landing
Audio 1:22:36 Auto pilot disconnect audio tone and stab trim noise
P1
1:22:55
checked
P2 1:22:59 Speed brakes up, reversers normal
NOISE 1:23:07 Noise of nose wheel rolling on the runway
P2 1:23:24 60 knots auto brake disarm
P1
1:23:31
Look at the runway surface
ATC 1:23:33 Jet 615 vacate via delta cross runway 19R
P2 Delta cross runway 19R
P1
1:25:26
Runway Surface Kitnaa Kharaabb hai yaar
P2 1:25:28 I swear you keep bouncing up down, up down, up
down.
The landing was carried out by PIC.
Co-pilot had informed PIC after landing that “aircraft was bouncing up down” after
landing.
There was no mention / recording of Co-pilot monitoring the aircraft attitude and
speed during landing
The DFDR readout was analyzed and following are the salient findings.
S. No GMT Radio
Altitude
(Feet)
CAS
(Kts)
Pitch Stab
Trim
Vert
G
Winds AP
Status
Remarks
1.
3:36:19
2749
204
2.46
6.81
1.04
282/9
AP 1
2.
3:37:20
2088
167
1.76
6.16
0.98
284/8.5
Both
3.
3:37:47
2013
162
1.76
5
0.94
285/8
Both
4.
3:38:19
1508
155
0.7
5.48
1
298/5
Both
11
S. No GMT Radio
Altitude
(Feet)
CAS
(Kts)
Pitch Stab
Trim
Vert
G
Winds AP
Status
Remarks
5.
3:38:55
1001
154
1.05
5.48
1.02
324/4
Both
6.
3:39:27
521
156
0.7
5.48
1.08
001/5.5
Both
7.
3:39:46
243
154
0.7
6.72
1
343/5.5
Both
8.
3:39:52
161
153
1.93
6.69
1.02
342/5
Off
9.
3:40:00
59
154
2.46
6.07
1.02
345/6
Off
10.
3:40:02
35
154
4.04
6.1
1.13
343/6
Off
11.
3:40:16
0
138
5.1
6.07
1.36
346/7
Off
Touch down
12.
3:40:19
0
127
9.14
6.13
1.21
350/7
Off
Point of Tail
Strike
PIC engaged both auto pilot from AP 1 at Radio Altitude of 2088 feet.
Both the auto pilot were disengaged at Radio Altitude of 161 feet.
Aircraft flare lasted for about 14 seconds (from 30 ft to MLG touchdown).
Distance from Threshold to touchdown approximately 1200m.
Aircraft touched down with a pitch of 5.1 °s and speed V
ref
-10 kts. (Vref was
148 kts)
Vertical G recorded at touchdown was 1.36.
04 seconds after touch down, the aircraft pitch reaches 9.14 °s where aft fuselage
and Tail Skid contacted the Runway.
During high speed descends maximum vertical speed was 1095 feet/min.
1.12 Wreckage and impact information.
The tail skid & aft lower part of fuselage got scrapped on Runway 19L during landing.
1.13 Medical and pathological Information:
Prior to operating the flight both the Cockpit crew had undergone pre-flight
medicals/Breath analyzer test at Mumbai and were found to be negative. After the incident
both the cockpit crews were not subjected to Breath analyzer test.
1.14 Fire:
There was no pre or post impact fire.
12
1.15 Survival aspects:
The serious incident was survivable. There was no Injury to any passenger or crew.
1.16 Tests and research:
Nil
1.17 Organizational and management information:
M/s Jet Airways (India) Ltd. is a Scheduled Airlines having valid DGCA SOP No. S-6A
in Category Passenger and Cargo which commenced operations on 5
th
May 1993. The
airlines operates a fleet of aircraft, which includes 04 Boeing 777-300 ER aircraft, 08
Airbus A330-200 aircraft,68 next generation Boeing 737-700/800/900 aircraft and 18 ATR
72-212A turboprop aircraft. M/s Jet Airways operates 68 destinations (47 Domestic + 21
international) and having approx 13900 employees.
1.18 Additional information:
Tail Strike during landing is more critical than the tail strike during take- off. During 2012-
2015, there have been three (03) serious incidents of tail strike during landing occurred to
Indian Scheduled airlines excluding this serious incident.
1.18.1 Flare and Touchdown Profile of B 737
The techniques mentioned are applicable to all landings including one engine inoperative
landings, crosswind landings and landings on slippery runways. Unless an unexpected or
sudden event occurs, such as wind shear or collision avoidance situation, it is not
appropriate to use sudden, violent or abrupt control inputs during landing. While carrying
out Stabilized approach when the threshold passes under the airplane nose and out of sight,
shift the visual sighting point to approximately 3/4 the runway length. Shifting the visual
sighting point assists in controlling the pitch attitude during the flare. Maintaining a
constant airspeed and descent rate assists in determining the flare point. Initiate the flare
when the main gear is approximately 15 feet above the runway by increasing pitch attitude
approximately 2° - 3°. This slows the rate of descent. After the flare is initiated, smoothly
retard the thrust levers to idle, and make small pitch attitude adjustments to maintain the
desired descent rate to the runway. Ideally, main gear touchdown should occur
simultaneously with thrust levers reaching idle. A smooth power reduction to idle also
assists in controlling the natural nose-down pitch change associated with thrust reduction.
Hold sufficient back pressure on the control column to keep the pitch attitude constant. A
touchdown attitude as depicted in the figure below is normal with an airspeed of
approximately V
ref
plus any gust correction. Do not trim during the flare or after
touchdown. Trimming in the flare increases the possibility of a tail strike.
13
1.18.2 Landing Flare Profile
The following diagrams use these conditions:
• 3° approach glide path
• flare distance is approximately 1,000 to 2,000 feet beyond the threshold
• typical landing flare times range from 4 to 8 seconds and are a function of approach
speed
• Airplane body attitudes are based upon typical landing weights, flaps 30, VREF 30 +
5 (approach) and VREF 30 + 0 (landing), and should be reduced by 1° for each 5 knots
above this speed.
• Threshold height for main gear and pilot eye level is shown in two Bar/Three Bar VASI
landing Geometry tables.
The pitch attitude increases slightly during the actual landing, but avoid over-rotating. Do
not increase the pitch attitude after touchdown; this could lead to a tail strike. Shifting the
visual sighting point down the runway assists in controlling the pitch attitude during the
flare. A smooth power reduction to idle also assists in controlling the natural nose down
pitch change associated with thrust reduction. Hold sufficient back pressure on the control
column to keep the pitch attitude constant. Avoid rapid control column movements during
the flare. Do not use pitch trim during flare or after touch down. Such actions are likely to
cause the pitch attitude to increase at touchdown and increase the potential for a tail strike.
Do not allow the airplane to float; fly the airplane onto the runway. Do not extend the flare
by increasing pitch attitude in an attempt to achieve a perfectly smooth touchdown. Do not
attempt to hold the nose wheels off the runway.
If the airplane should bounce, hold or re-establish a normal landing attitude and add thrust
as necessary to control the rate of descent. Thrust need not be added for a shallow bounce
14
or skip. When a high, hard bounce occurs, initiate a go-around. Apply go-around thrust and
use normal go-around procedures. Do not retract the landing gear until a positive rate of
climb is established because a second touchdown may occur during the go-around.
Bounced landings can occur because higher than idle power is maintained through initial
touchdown, disabling the automatic speed brake deployment even when the speed brakes
are armed. During the resultant bounce, if the thrust levers are then retarded to idle,
automatic speed brake deployment can occur resulting in a loss of lift and nose up pitching
moment which can result in a tail strike or hard landing on a subsequent touchdown.
1.18.3 Normal Touchdown Attitude
The following figures illustrate the effect of airspeed on body attitude on touchdown. It
shows normal touchdown attitude for flaps 30. If flare control and thrust are excessive near
touchdown, the airplane tends to float in ground effect. With proper airspeed control and
thrust management, touchdown occurs at no less than V
ref
- 5. The illustration shows that
touchdown at a speed significantly below V
ref
seriously reduces aft fuselage-runway
clearance.
15
1.18.4 Body Clearance at Touchdown
The following figures show aft fuselage-runway clearance in relation to pitch angle
with all main gear tires on the runway.
Body Clearance above Ground
1.18.5 Landing of VT-JGE
The approach was normal and met the company stabilized approach criteria. The second
autopilot was engaged at 2088 feet at a distance of 7.2 Nm ILS DME. Contrary to an
approach mode with single auto pilot the Dual mode adds a stabilizer trim bias of nose
up and this needs to be compensated for if the crew takes over manually. The following
extract of Boeing 737 FCOM explains that:
“The stabilizer is automatically trimmed an additional amount of nose up. If the Auto
pilot subsequently disengages, forward control column force may be required to hold
the desired pitch attitude.”
16
As per Boeing FCTM extracted below it is recommend to disengage autopilot at
approximately 300 to 600 feet AFE if a manual landing is planned. This allows the pilot
to establish airplane control before beginning the flare. The auto pilot was disengaged
at 161 ft RA .The note mentioned in AFM is
“When a manual landing is planned from an approach with autopilot connected, the
transition to manual flight should be planned early enough to allow the pilot time to
establish airplane control before beginning the flare. The PF should consider
disengaging the auto pilot and disconnecting the auto throttle 1 to 2 minutes before the
threshold or approximately 300 to 600 feet above the field elevation.”
Due to the late autopilot disengagement PIC did not have adequate time to apply
sufficient nose down trim to counter the bias added by the autopilot. The DFDR and
CVR audio confirm small amount of nose down trim applied after autopilot
disengagement and prior to flare.
The FCTM extract below indicates a flare time of 4 to 8 seconds for a normal landing
whereas this landing flare of VT-FGE lasted 14 seconds. This may have been
influenced by the PIC attempting a smooth landing.
Speed at touchdown was 138kts which was 10kts below selected Vref (148kts). With
the lower speed the aft body clearance is reduced thereby increasing the risk of tail
strike as shown in the diagram below.
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1.18.6 Tail Skid Assembly.
B-737-800 aircraft VT-JGE has a single position tail skid. It is used to protect the Fuselage
during a tail strike. It will protect on rotation and during landing.
To protect the aft lower fuselage from over rotation damage the Boeing 737-800/900 is
equipped with tail skid. It consists of a sort-of-shock absorber cartridge, a skid fairing and
a skid shoe, where the last two parts are outside the fuselage.
A light touch of aircraft tail to runway causes the shoe to wear off, indicating the amount
of wear and is an indication when the shoe needs to be replaced.
A firm touch crushes skid disappears indicated by colored decals. If the green decal is still
visible the skid is still “serviceable” but if the green decal disappears inside the fuselage,
the red decal indicates that the skid must be replaced.
When the touch is more than firm, the skid disappears totally inside the of fuselage and a
safety pin (fuse pin) allows the cartridge to pivot inside (other than crushing) there by
protecting the aircraft structure against massive loads.
The red & green indicator is checked during every walk around inspection to ensure an
inadvertent tail strike did not occurred on the previous takeoff or landing. Due to longer
fuselage length B-737-400/800/900 series are prone to tail strike.
Other, B-737-800 SFP (Short Field Performance) has a two position tail skid. This has a
hydraulic actuator that deploys when the plane is departing and on arrival so that it has
extra performance
Retractable tail skid that extends on take offs and landings which is under control of the
supplemental proximity sensing Electronic Unit (SPSEU) and operates with hydraulic
system.
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Tail Skid
19
Tail Skid Assembly
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Tail Skid without damage
1.19 Useful or effective investigation techniques: NIL
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2. ANALYSIS
2.1 SERVICEABILITY OF THE AIRCRAFT
B737-800 aircraft VT-JGE (MSN 32663) was manufactured in year 2004. On the day
of incident, the aircraft VT-JGE had logged 38078 airframe hours and 16650 cycles and
was holding a valid Certificate of Airworthiness and flight Release prior to flight. The
Jet Airways is holding valid Scheduled Air Operator Permit (SOP).
The aircraft and engines were being maintained under continuous maintenance as per
approved maintenance program consisting of calendar period based maintenance and
Flying hours /cycles based maintenance.
The last layover inspection was carried out at 38069:54 Airframe hrs and 16643 cycles
on 13-01-2015 at Mumbai.
The load and trim sheet was prepared before flight and C.G. of the aircraft was within
the operating limits.
2.2 WEATHER :
At the time of approach 0336 UTC, ATC reported visibility of 800 meters, runway 19L
RVR 1200m, MID 1000m, winds 350/05kts.Though visibility was less but it was above
minima and aircraft carried out ILS approach at runway 19L.
2.3 ANALYSIS OF FLIGHT DATA RECORDERS
The aircraft is fitted with Solid State CVR & DFDR. Analysis of CVR reveals that
1) Autopilot was disconnected after Minimums warning and PIC was adjusting
Stabilizer trim during landing.
2) PIC after landing mentioned to co-pilot that the runway surface was not good.
3) Co-pilot informed PIC that during landing aircraft was bouncing up & down.
4) There was no mention / recording of Co-pilot monitoring the aircraft attitude and
speed during landing.
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Analysis of DFDR reveals that
1) Autopilot was disengaged at 161ft RA and aircraft was landed manually.
2) Slight nose down trim was applied after taking over manual control prior to
flare
3) The aircraft flare lasted 14 seconds (from 30ft to MLG touchdown).
4) Distance from Threshold to touchdown approximately 1200m.
5) Aircraft touched down with a pitch of 5.1° and speed of Vref (-10) Kts.
6) Four seconds after touchdown the pitch increased to 9.14 ° when the tail strike
occurs at this point.
7) G recorded at touchdown was 1.36.
8) As per the DFDR readout the aircraft flare was for more time.
2.4 PILOT HANDLING OF THE AIRCRAFT:
PIC at 6000 feet requested ATC (approach) for high speed descend which was approved
by ATC. DFDR reveals a maximum vertical speed of 1095 feet/min during high speed
descend between 6000 to 3000 feet. The landing was carried out by PIC at Runway
19L. As visibility was less, PIC engaged both Auto-pilots at Radio Altitude of 2088
feet. Autopilot was disengaged at 161ft RA whereas as per As per Boeing FCTM it is
recommend to disengage autopilot at approximately 300 to 600 feet AFE if a manual
landing is planned. This allows the pilot to establish airplane control before beginning
the flare. During dual mode autopilot approach, stabilizer trim automatically added nose
up and this needs to be compensated for if the crew takes over manually.
PIC applied small amount of nose down trim after autopilot disengagement and prior
to flare. The flare lasted for 14 seconds and aircraft touched approximately 1200m from
threshold .As per FCTM a flare time of 4 to 8 seconds is for a normal landing .The
speed at touchdown was 138kts, which was 10kts below selected Vref (148kts). The
aircraft touched down with a pitch attitude of 5.1°. However after three seconds the
attitude increased to 9.14 ° when tail strike occurred.
2.5 CIRCUMSTANCES LEADING TO THE INCIDENT:
The flight from Mumbai to Kolkata was uneventful till touchdown. The visibility at the
time of landing was 800 m and ATC assigned Runway 19 L for landing, PIC decided to
carry out dual auto pilot approach with the intention of carrying out a manual landing.
During landing auto pilot was disengaged at 161ft RA and PIC applied small amount of
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nose down trim after flare. Aircraft touched down with a pitch of 5.1° and speed of 138
kts, which was 10kts below selected Vref (148kts). The flare lasted for about 14 seconds
and the aircraft pitch reached 9.14° resulted into tail strike.
3. CONCLUSIONS:
3.1 FINDINGS:
1) The certificate of Airworthiness, Certificate of Registration, and CRS of the
aircraft was valid on the date of incident.
2) The aircraft was certified and maintained in accordance with prescribed
procedures. There was no evidence of defects or malfunction in the aircraft which
could have contributed to the incident.
3) The flight crew was certified and qualified to conduct the flight. They had
undergone the requisite pre-flight medical examination and were certified as not
being under the influence of alcohol.
4) The CG of the aircraft was within the prescribed limits.
5) All navigation and approach aids were functional and were operating normally at
the time of incident.
6) The PIC had a total flying experience of 5248:10 hrs of which 1583:24 hrs were
as PIC on type. Co-Pilot had a total flying experience of 4932:46 hrs and 4557:00
hrs as P2 on type.
7) As visibility was less, PIC engaged both Auto-pilots at Radio Altitude of 2088
feet. Autopilot was disengaged at 161ft RA whereas as per as per Boeing FCTM
autopilot to be disengaged at approximately 300 to 600 feet AFE if a manual
landing is planned. This allows the pilot to establish airplane control before
beginning the flare.
8) During dual mode Autopilot approach, stabilizer trim automatically added nose
up and this needs to be compensated if the crew takes over manually.
9) PIC applied small amount of nose down trim after autopilot disengagement and
prior to flare which was not adequate.
10) The flare lasted for 14 seconds and aircraft touched approximately 1200m from
threshold. As per FCTM a flare time of 4 to 8 seconds is for a normal landing.
11) Speed at touchdown was 138kts which was 10kts below selected Vref (148kts).
The aircraft touched down with a pitch attitude of 5.1°. However, after three
seconds the attitude increased to 9.14°.
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25
Damage to Belly of aircraft
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Damage to Belly of aircraft
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Damage to Belly of aircraft
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Damage to Tail Sid Shoe and decal markings
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Screen shot Image of VT-JGE landing using Airfase Software