B773, Hong Kong China, 2017
B773, Hong Kong China, 2017
On 28 April 2017, a Boeing 777-300 made a 3.2g manual landing at Hong Kong, which was not assessed as such by the crew and only discovered during routine flight data analysis, during a Final Line Check flight for a trainee Captain. The Investigation noted that the landing technique used was one of the reasons the Check was failed. The trainee had been an experienced 737 Captain with the operator who had returned from 777 type conversion training with another airline and was required to undertake line training to validate his command status in accordance with local requirements.
On 28 April 2017, a Boeing 777-300 (VT-JEQ) was being operated by Jet Airways on a scheduled international passenger flight from Delhi to Hong Kong as 9W-78 during which a trainee Captain was undergoing the first sector of his Final Line Check. After an ILS approach in day VMC, the landing was firm although not assessed as excessively so and was therefore not recorded as such but subsequently discovered to have resulted in a recorded 3.2 g, prompting an Investigation. There were no injuries to the 177 passengers on board.
An Investigation in accordance with Annex 13 principles was carried out by the Indian DGCA. The FDR was removed and its relevant data were successfully downloaded but as relevant data on the CVR would have been overwritten, it was not removed.
The 53 year-old Training Captain in command and acting as examiner had a total of 14,421 flying hours experience which included 1,049 hours on type, having achieved his type rating 4½ years earlier and examiner rating soon afterwards based on his previous experience as a Boeing 737 examiner. Since flying the 777, he had made 13 flights to Hong Kong, the most recent of which had been just over three years before the incident. The 43 year-old trainee 777 Captain had joined Jet Airways in 2002 and had initially flown the Boeing 737 as a First Officer (3,729 hours) and then as a Captain (5,697 hours). He had been sent to Etihad Airways for type conversion to the Boeing 777 and then undertaken some limited command flying with them before returning to Jet Airways in March 2016. He was then required to undertake further training and checks in order to gain approval to operate as a 777 commander for an Indian operator as specified for holders of a P1 type rating issued elsewhere. This required six sectors of supervised line flying and 10 consecutive Line Check flights of which the flight under investigation was rostered as the tenth and final. He had made 2 previous flights to Hong Kong as a 777 Captain whilst with Etihad Airways, the most recent in August 2016, but had not been there during his Jet Airways training flights.
It was established that after a week off duty, the trainee Captain had positioned from Mumbai to Delhi early in the morning of the previous day and then been provided with hotel accommodation for at least 12 hours before the late evening report for the Hong Kong flight. The Training Captain in command was based in Delhi. The flight took off from Delhi in the early hours of 28 April and just over 3½ hours later, began its descent into Hong Kong. An ILS approach to runway 07L was made with the aircraft fully established by 2000 feet with no significant deviation thereafter. As the aircraft passed 1000 feet agl, the AP and A/T were engaged and the aircraft was configured for 30 flap landing with speedbrakes armed. At a recorded 843 feet agl, the AP was disconnected and the approach was continued at approximately VREF+5 and at an average of 800 fpm with the reported surface wind from 050° at 8 knots.
The landing flare was initiated at a recorded 36 feet agl and pitch attitude +0.7° to +3.25° which arrested the descent rate at 700 fpm before it began to reduce. The Training Captain did not intervene “as he felt that it would aggravate the situation” and was aware that the trainee had flown in command with Etihad Airways on the 777 and had already completed nine satisfactory route checks with Jet Airways. Touchdown subsequently occurred with a recorded 3.23g vertical load and an “after landing shudder” was reported to have been felt by the crew. The remainder of the landing roll was normal. It was noted that the landing weight was 31 tonnes below the 251 tonne MLW. The Training Captain subsequently recorded on his assessment form that the planned Final Line Check sector had been “unsatisfactory” due to (amongst other observations) the “inadequate flare” and “touchdown short of course point”. It was noted that the trainee involved had finally gained his command on type some 3½ months after the investigated event.
Four days after it had occurred, the exceedance was automatically detected by the aircraft operators OFDM programme and the flight safety department sent a corresponding email notification to the engineering department. The following day, Phase 1A and 1B of the required airframe inspection were carried out with no findings which meant that Phase 2 of this inspection was not required.
Prompted by the finding that the landing had breached airframe structural limits despite this being considered unlikely by an experienced Training Captain, a very detailed analysis of the landing was performed for the Investigation by Boeing. This showed that just prior to the landing, the recorded rate of descent had been 486 fpm. On touchdown, “three successively increasing peaks were observed in the normal load factor of 1.65. 1.82, and 3.23, the final one just 0.7 seconds after the estimated touchdown time”. Touchdown had occurred with a left bank of about 1.3° at VREF+3 and after it, there had been a right rudder pedal input to de-crab the aircraft with the recorded lateral acceleration reaching 0.38 g to the right “as the speedbrakes extended and the weight of the aircraft settled onto the main gear”.
The Investigation noted that the flight data indicated that during the flare, FDR data showed that there had been “frequent push and pull inputs” which had resulted in the pitch attitude achieved during the flare being less than required and the rate of descent too high, an observation supported by comparison with three other ‘normal’ landings at Hong Kong. Having noted that the trainee Captain had claimed during the Investigation that “he was not adequately rested” before the flight even though his duty had been within the applicable flight time limitations, it was speculated that his poor performance may have also been affected by his “anxiety and fatigue”.
Boeing analysis also considered what AMM inspections were required after a suspected or actual hard landing. If a landing were to be reported as "hard" by a flight crew then Phase IA and IB inspections are required prior to the next flight but if flight data was immediately available, “an evaluation could have been performed to determine if the Phase 1B inspection could be waived”. However, in the case under investigation, the vertical acceleration had been above the AMM threshold, so that the Phase IB inspection could not have been waived. However if, as in the investigated case, there is no pilot report and only flight data is available, both Phase 1 inspections are at the airline's discretion. It was also noted that assuming a zero runway slope, the 486 fpm rate of descent recorded was below the landing gear design limit. Boeing also stated that “flight crew's judgment is the most reliable criterion to use for determining if a hard landing has occurred - data alone are insufficient to make this determination”.
It was noted that although there is no automatic display in the 777 flight deck of the rate of descent at touchdown, there is a ‘Maintenance Access Terminal’ behind the right hand pilot seat which can be used to generate a "sink" report which provides values which can be input to the C of G Load Factor Chart to determining a vertical load factor.
The Jet Airways OM Part A was noted to say that “typical sink rates at touchdown are of the order of 120 to 240 fpm and even a hard landing rarely exceeds 360 fpm”. It also noted that aircraft are certified for a sink rate of up to 600 fpm at MLW and a sink rate of up to 360 fpm at MTOW and stated that “a hard landing shall be considered to be any unusual or abnormally hard touchdown” following which “it is prudent for flight crew to (make a) report so that a special aircraft inspection can be carried out by Engineering”.
Additional findings during the Investigation which, in the event, were not directly relevant to it, were noted as having including the fact that Jet Airways classified Hong Kong as a Category ‘B’ aerodrome. This meant that its OM ‘D’ required that pilots receive a specific briefing or self-briefing on such destinations. In the case of Hong Kong, it was observed that this briefing information did not include a range of subjects recommended for pilot awareness in the Hong Kong AIP which should have been covered in the OM Part ‘C’ to enable reference to be made to them in the briefing material.
It was also noted that in general, many aircraft handling events occur below 50 feet agl where it can become difficult for a supervising Captain to make a decision and act. It was noted that based on related regulatory requirements for pilot training, airline operators including Jet Airways had developed training guidance but that only a few of them were using a suitably comprehensive list of such potential issues.
The Cause of the investigated event was determined as “frequent change in pitch input during the landing phase of flight & touchdown with inadequate flare”.
Two Contributory Factors were also identified as “the fatigue of the trainee pilot” and “lack of familiarity with the airport at Hong Kong”.
Five Safety Recommendations were made as a result of the Investigation as follows:
- that Airline Operators reiterate the procedures associated with the reporting of suspected hard landings and the information available to assist decision making on reporting for the aircraft types operated.
- The Directorate General of Civil Aviation (DGCA) consider standardisation of the check pro forma for pilot training and include the following elements as part of the training/assessment:
- Over Controlling during Approach - No Retard
- High Rate of Descent after 50 Feet - Weak Flare - Take Over
- Over Flare - Balloon
- High Flare followed by a Go Around
- Strong Cross winds - Drift at low altitude
- High Bank Input before/during flare
- Take off at RTOW - Fast Rotation/Early Rotation/Over Rotation
- Over Controlling in roll during the flare and early reduction of thrust - Take Over
- The Directorate General of Civil Aviation (DGCA) consider directing Airline Operators to conduct Supervised Line Flying to an International Destination where the subsequent Route Check is planned.
- that Jet Airways review its process of providing programmed briefing and include all the information mandatorily required by DGCA-India regulations and local regulations.
- that Airline Operators’ rostering sections give due consideration when rostering pilots for a Line Assessment/Route Check.
The Final Report of the Investigation was completed on 18 October 2018 and subsequently released.