|
|
Post by Jeff on Aug 14, 2018 13:58:57 GMT
Incident: Jet Airways B773 at London on Aug 30th 2016, unsafe departure
By Simon Hradecky, created Thursday, Oct 6th 2016 16:00Z, last updated Friday, Aug 10th 2018 15:02Z
A Jet Airways Boeing 777-300, registration VT-JEK performing flight 9W-117 from London Heathrow,EN (UK) to Mumbai (India) with 231 passengers and 15 crew, lined up Heathrow's runway 27L at taxiway S4E, about 1200 meters/4000 feet down the runway (total runway length 3660 meters/12000 feet leaving about 2400 meters/8000 feet remaining for that takeoff). The aircraft departed, climbed through 1000 feet MSL about 3200 meters/1.7nm past the runway end and continued the flight to Mumbai for a safe landing about 8:10 hours after departure.
However, local residents complained to police about a low flying aircraft, that had barely cleared the aerodrome perimeter fence. Police contacted Air Traffic Control at Heathrow Airport, who identified the aircraft and notified United Kingdom's AAIB. The AAIB opened an investigation into the occurrence and informed India's Directorate General of Civil Aviation (DGCA), who suspended both captain and first officer of the flight pending the investigation.
The airline reported there had been no injuries and no damage, the airline however investigates the occurrence as part of their active safety management, too. The aircraft performed an intersection departure, thus not using the full runway length, however, did not climb to required height in time and crossed the airport perimeter wall and traffic on the road just past the wall at very low height.
On Aug 10th 2018 India's AAIB released their final report stating the aircraft had crossed the airport boundary at 13 feet AGL and an adjacent road at 30 feet AGL (according to the airport's noise monitoring systems) and concluding the probable cause of the serious incident was:
Wrong selection of aircraft take- off performance by the Commander despite the Co-pilot selecting the right take-off performance initially but the commander overruled her take-off performance selection.
|
|
|
|
Post by keefyboy on Aug 14, 2018 15:19:23 GMT
Jeff
Is it common practice for 777's to take off using only 8000 feet of runway at Heathrow? Whilst I'm sure 777's can manage it with a full load, I'm surprised that air traffic control don't factor in that extra 4000 feet of runway to provide an improved safety margin for wide bodies? Just a thought.
|
|
|
|
Post by Jeff on Aug 14, 2018 19:42:31 GMT
Its not usual for them to clear the fence at 13ft though!!! They were offered full length but declined
The first time initiation of SW4 intersection departure by the crew (both Commander andCo-pilot).
The AAIB reported two NOTAMs were in effect indicating taxiway S east of taxiway V was unavailable effectively closing the entry taxiways S1-S3, however, taxiway S4 was available for line up. In addition, if the aircraft needed a full length takeoff, they could have crossed runway 27L and taxied via the northern taxiways to the entry taxiways NB1, N2E, N2W or N3. The crew declined the offer of a full length takeoff and advised departure from S4 was acceptable.
The aircraft was departing with a gross mass of 296,885 kg, which was below the maximum takeoff mass of 318,646 kg for departure from S4 intersection, the departure thus was not performance limited. After receiving the final load sheet both flight crew ran their takeoff performance computations independently. The captain (45, ATPL, 13,436 hours, 943 hours on type) selected "First 4" into the option for the intersection, the first officer (32, CPL, 2,446 hours total, 1,198 hours on type) selected "SW4" into the option. When the crew compared their results, the first officer changed her intersection options to "First 4", too.
When the option "First 4" was selected, despite it's suggestion the performance would be computed for the 4th intersection, the default output of the program (with the other results upon selection) indicated the performance of a full length takeoff with a takeoff distance available of 3,349 meters/10985 feet whereas only 2,589 meters/8492 feet were available from intersection S4 (Editorial note: the report does not mention the correct takeoff performance data). The crew therefore used an assumed temperature of 45 degrees for a de-rated takeoff about 10% below available takeoff thrust. Computed V1 was 163 KIAS, Vr 167 KIAS and V2 171 KIAS.
According to analysis by Boeing based on the quick access recorder (QAR) the takeoff rotation commenced 556 meters/1823 feet before the runway end, the aircraft became airborne 97 meters/318 feet before the runway end, crossed the runway end at 16 feet radalt and crossed the perimeter road at 112 feet radalt.
The AAIB analysed that based on the selected V1 the required field length would have been 11,000 feet, with an all engine operating distance to liftoff of 7393 feet and an engine out liftoff distance of 9828 feet, while only 7715 feet were available. The AAIB wrote: "To meet the required runway field length for dispatch, the takeoff run should have started no farther than approximately 1001 feet from the runway threshold. The airplane did not meet the 35 feet screen height requirement when crossing the end of the runway and would not have had enough runway
|
|
