Singapore B773 at Melbourne on Oct 9th 2016, tower observes tailstrike on departure

Last Update: April 27, 2017 / 13:27:16 GMT/Zulu time

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Photo of Singapore Airlines 9V-SYG, Boeing 777-300 — Singapore Airlines 9V-SYG, Boeing 777-300 (Photo credit: Aero Icarus / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Oct 9, 2016

Classification
Incident

Airline
Singapore Airlines

Flight number
SQ-238

Departure
Melbourne, Australia

Destination
Singapore, Singapore

Aircraft Registration
9V-SYG

Aircraft Type
Boeing 777-300

ICAO Type Designator
B773

Airport
Melbourne International Airport, Melbourne

Airport ICAO Code
YMML

A Singapore Airlines Boeing 777-300, registration 9V-SYG performing flight SQ-238 from Melbourne,VI (Australia) to Singapore (Singapore), departed Melbourne's runway 34 when tower observed sparks and smoke from the tail section of the aircraft as the aircraft rotated between taxiways F and C (between 1800 and 3300 meters down the runway) and assumed the aircraft's tail had contacted the runway surface during rotation. The runway was closed, and air traffic control contacted the flight crew reporting tower's observations. A runway inspection revealed no metal debris on the runway, however scrape marks and damage were found on the runway surface. Approach controllers instructed several arriving aircraft to enter high level holds due to the runway closure as result of a tail strike and damage to the runway, initally also telling aircraft that there was debris on the runway. The flight crew decided in absence of any abnormal indications to continue the flight, climbed the aircraft to FL320, later step climbing to FL340 and FL360 and landed the aircraft safely on Singapore's runway 20C about 7.5 hours after departure. There were no injuries, an inspection of the aircraft revealed the tail skid assembly did make contact with the runway surface, the tail skid assembly is being replaced.

The runway was closed for about 30 minutes until repairs were completed.

ATC reported there were sparks and smoke from the tail of the aircraft as it departed Melbourne, debris was observed on the runway.

The airport reported Tower observed sparks and smoke, however, no debris was found on the runway.

The airline confirmed that ATC had informed the flight crew about a possible tail strike, however, the crew had no indication of a tail strike and decided to continue to Singapore, where the aircraft is being inspected. A visual inspection revealed the tail skid assembly made contact with the ground, however, the fuselage did not make contact with the ground. The tail skid assembly is being replaced.

On Oct 11th 2016 The Aviation Herald learned that preliminary inspection results showed the center of gravity as well as computed and set takeoff performance were correct, the aircraft rotated at Vr however reached about 4 degrees/s rate of rotation, at the same time a wind gust reduced the IAS with decreasing trend prompting the pilot monitoring to call out "Speed!", the pitch attitude reached a maximum of +10.7 degrees with the main gear still on the ground. The tail skid assembly performed to its design capabilities and protected the pressurized part of the aircraft. Following communicaton by ATC the flight crew inquired with cabin crew about any observations, cabin crew reported hearing a bang during rotation. The flight crew worked the "unannounciated tail strike" checklist and monitored pressurization throughout the flight.

The occurrence aircraft resumed service after about 47.5 hours on the ground.

On Apr 27th 2017 the ATSB released their final report concluding the probable cause of the incident was:

- The tail skid contact was a result of airspeed stagnation due to gusty atmospheric conditions which prolonged the time to lift-off, allowing the pitch attitude to exceed the tail skid contact attitude.

- The use of a higher take-off thrust setting would most likely have reduced the required runway length and minimised the aircraft exposure to gusty atmospheric conditions during rotation and lift-off.

The ATSB analysed:

Analysis of the aircraft flight data showed multiple instances of airspeed stagnation from 77 kt computed airspeed through rotation initiation at 178 kt (Vr = 178 kt) and initial climb. Rotation was initiated at a computed airspeed of 178 kt (at Vr) at approximately 0.5 degrees per second initially before increasing to approximately 3 to 4 degrees per second. As rotation was initiated, the headwind component decreased 12 kt, the computed airspeed stagnated and reduced to 173 kt (Figure 2). Lift-off occurred at a pitch attitude of 10.7 degrees. The tail skid contact attitude is 8.9 degrees.

Metars:
YMML 090230Z 36040G52KT CAVOK 17/08 Q1003 FM0230 SEV TURB BLW 5000FT
YMML 090219Z 36031G43KT CAVOK 18/08 Q1003 FM0219 SEV TURB BLW 5000FT
YMML 090207Z 01042G57KT CAVOK 17/07 Q1003 FM0207 SEV TURB BLW 5000FT
YMML 090200Z 01041KT CAVOK 17/08 Q1003 FM0200 SEV TURB BLW 5000FT
YMML 090130Z 01042G55KT CAVOK 15/08 Q1003 FM0130 SEV TURB BLW 5000FT
YMML 090100Z 01039G51KT 9999 FEW020 BKN165 BKN230 15/08 Q1005 FM0100 SEV TURB BLW 5000FT
YMML 090038Z 01045G58KT 9999 FEW020 BKN155 BKN200 16/09 Q1006 FM0038 SEV TURB BLW 5000FT
YMML 090030Z 36032G47KT 9999 FEW020 BKN165 BKN200 15/09 Q1007 FM0030 SEV TURB BLW 5000FT
YMML 090030Z 36032G47KT 9999 FEW020 BKN165 BKN200 15/09 Q1007 FM0030 SEV TURB BLW 5000FT
YMML 090000Z 36034G49KT 9999 FEW020 SCT120 BKN155 14/08 Q1008 FM0000 SEV TURB BLW 5000FT
YMML 082330Z 36040G53KT 9999 FEW030 SCT140 BKN155 14/07 Q1009 FM2330 SEV TURB BLW 5000FT
YMML 082300Z 36029G41KT CAVOK 14/07 Q1008 FM0030 35035G55KT CAVOK FM2300 MOD/SEV TURB BLW 5000FT TILL 2400 FM0000 SEV TURB BLW 5000FT
YMML 082230Z 01029G39KT CAVOK 14/07 Q1008 FM2230 MOD/SEV TURB BLW 5000FT TILL 2400 FM0000 SEV TURB BLW 5000FT
YMML 082200Z 01033G44KT CAVOK 13/07 Q1009 FM2200 MOD/SEV TURB BLW 5000FT TILL 2400 FM0000 SEV TURB BLW 5000FT
YMML 082135Z 36031G41KT CAVOK 13/06 Q1010 FM2135 MOD/SEV TURB BLW 5000FT TILL 2400 FM0000 SEV TURB BLW 5000FT
YMML 082130Z 36033KT CAVOK 13/06 Q1010 FM2130 MOD/SEV TURB BLW 5000FT TILL 2400 FM0000 SEV TURB BLW 5000FT