Singapore B744 at Auckland on Dec 11th 2019, engine pod strike during go around

Last Update: October 26, 2020 / 16:23:47 GMT/Zulu time

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Incident Facts

Date of incident
Dec 11, 2019

Classification
Incident

Aircraft Registration
9V-SFO

Aircraft Type
Boeing 747-400

ICAO Type Designator
B744

Airport ICAO Code
NZAA

A Singapore Airlines Cargo Boeing 747-400, registration 9V-SFO performing freight flight SQ-7298 (dep Dec 10th) from Sydney,NS (Australia) to Auckland (New Zealand), was on final approach to Auckland's runway 05R when the crew initiated a go around form very low height, the #1 engine pod (PW4056, outboard left hand) struck the ground. The aircraft climbed to 5000 feet, positioned for another approach to runway 05R and landed on runway 05R without further incident about 13 minutes after the go around.

The occurrence aircraft is still on the ground in Auckland about 32 hours after landing.

The aircraft had suffered another #1 engine pod strike in Sydney 2 weeks earlier, see Incident: Singapore B744 at Sydney on Nov 28th 2019, engine pod strike during go around.

In 2020 Singapore's AIB (SAIB) released their final report dated Aug 17th 2020 concluding the probable causes of the incident were:

While the operator indicated that it had adopted a competency-based training and assessment system to ensure that, at the completion of training, pilot trainees would be able to execute safe crosswind landings, the investigation team noted that, during simulator checks, it was up to the pilot trainees to use whichever technique they liked to land the aircraft successfully in a crosswind scenario. They were not required to demonstrate during simulator checks that they are able to apply all the three crosswind landing techniques.

The incident approach was the first time the PIC chose to use the ‘touchdownin-a-crab’ technique in line flying.

The aircraft pitched up shortly after touchdown. This was probably the result of the constancy of the column control input and the deployment of the speedbrakes, as identified in the Flight Crew Training Manual.

The PIC lost sight of the runway end lights and believed that the aircraft had momentarily become airborne even though the aircraft had remained on ground.

As the aircraft tracked towards the right after touchdown and believing that the aircraft was airborne, the PIC applied left aileron to align the aircraft with the runway centreline. This caused the left wing to bank to the left and the No. 1 engine to scrape the runway.

The operator was aware of the hazard of banking an aircraft when the aircraft was very close to the ground and had in place a Flight Data Analysis Programme (FDAP) which looked for abnormal aircraft roll during landing. The FDAP would capture abnormal aircraft roll during landing events only if it occurred within 10sec from touchdown. Other than this approach incident and another engine pod strike occurrence on 28 Nov 2019, there had been no other abnormal aircraft roll events captured.

The AIB described the sequence of events:

At about 0332LT, during the approach to Runway 05R at Auckland Airport, when the aircraft was at a height of about 2,400ft, the Pilot-in-Command (PIC, 63, ATPL, 22,637 hours total, 4,586 hours on type), who was performing Pilot Flying (PF) duties, disengaged the auto-pilot and flew the Instrument Landing System (ILS) approach manually.

There was a right crosswind of about six to seven knots at Auckland Airport. The PIC employed the ‘touchdown-in-a-crab’ technique for the approach, which entailed in this instance pointing the aircraft about 5° to the right of the runway centreline. The PIC planned to touch down on the runway slightly to the right of the runway centreline instead of on the centre of the runway. His consideration was that this would allow a greater margin of safety from an excursion off the left edge of the runway should the aircraft be forced downwind during touchdown.

According to the PIC, he executed the flare at about 30ft. The aircraft touched down on the runway at about 0335LT, the speedbrakes were automatically deployed and the aircraft pitched up shortly after touchdown. The PIC said that he lost sight of the runway end lights when the aircraft pitched up and sensed that the aircraft bounced. He then sensed that the aircraft was moving towards the right edge of the runway and so he called for a go-around and manually increased the throttles. At about the same time, the PIC also applied left aileron to roll the aircraft towards the left to align the aircraft with the runway centreline. Subsequently the aircraft got airborne.

The Air Traffic Control (ATC) observed what looked like sparks coming from the left wing of the aircraft and informed the flight crew that some part of the aircraft might have contacted the runway during the go-around. The flight crew acknowledged the ATC and subsequently landed at the airport at 0350LT without further incident.

The SAIB analysed:

the aircraft pitched up shortly after touchdown. The FDR data showed that, upon touchdown, the control column input (i.e. the pull force on the control column) was relatively constant and that the speedbrakes were deployed soon after touchdown. As identified in the FCTM (see paragraph 1.11.4.1), the constancy of the column control input and the deployment of the speedbrakes would result in pitching up of the aircraft.

The PIC said that he lost sight of the runway end lights when the aircraft pitched up and sensed that the aircraft bounced (even though the aircraft did not bounce). The disappearing of the runway end lights made him believe that the aircraft was momentarily airborne.

Believing that the aircraft was airborne and sensing that the aircraft was moving towards the right edge of the runway (FDR data showed that the aircraft was tracking towards the right after touchdown), the PIC called for a go-around and manually increased the throttles, while applying at the same time left aileron to roll the aircraft towards the left to align the aircraft with the runway heading.

The investigation team believed that it was at this moment that the No. 1 engine struck the runway because of the aircraft’s bank angle (which the FDR data showed to be about 7°), resulting in what appeared to ATC to be sparks coming from the left wing of the aircraft.

The investigation considered whether the Blackhole Effect could possibly explain why the PIC sensed that the aircraft had bounced but concluded that it was unlikely as the aircraft had already touched down on the runway. Moreover, the flight recorder data showed that the aircraft remained on the ideal glidepath from 2,000ft until it touched down. The lack of visual cues in the vicinity of the runway, even if it had been the case in this approach incident, would not have had an effect to the PIC when the aircraft was on the runway.

Crosswind landing

To deal with the crosswind, the PIC opted to use the ‘touchdown-in-a-crab’ technique. However, while he was aware that the FCTM had stipulated that pilots should aim at having the main landing gears touch down on the centre of the runway, he decided that he should aim at having the main landing gears touch down slightly to the right of the runway centreline. He believed this would allow a greater margin of safety from an excursion off the left edge of the runway should the aircraft be forced downwind during touchdown.

Metars:
NZAA 101600Z AUTO 13004KT 9999 NCD 13/09 Q1013 NOSIG=
NZAA 101530Z AUTO 14006KT 9999 NCD 13/09 Q1013 NOSIG=
NZAA 101500Z AUTO 14007KT 9999 NCD 14/10 Q1013 NOSIG=
NZAA 101430Z AUTO 14007KT 9999 NCD 14/11 Q1013 NOSIG=
NZAA 101400Z AUTO 15006KT 9999 NCD 14/11 Q1013 NOSIG=
NZAA 101330Z AUTO 12005KT 9999 NCD 15/13 Q1013 NOSIG=
NZAA 101300Z AUTO 14005KT 9999 NCD 15/12 Q1013 NOSIG=
NZAA 101230Z AUTO 14006KT 9999 NCD 16/13 Q1014 NOSIG=
NZAA 101200Z AUTO 16006KT 9999 NCD 16/12 Q1014 NOSIG=
NZAA 101130Z AUTO 17005KT 9999 NCD 17/12 Q1014 NOSIG=
NZAA 101100Z AUTO 18004KT 9999 NCD 17/12 Q1015 NOSIG=
NZAA 101030Z AUTO 20004KT 9999 NCD 17/13 Q1015 NOSIG=
NZAA 101000Z AUTO 19005KT 9999 FEW080/// 17/13 Q1015 NOSIG=
Incident Facts

Date of incident
Dec 11, 2019

Classification
Incident

Aircraft Registration
9V-SFO

Aircraft Type
Boeing 747-400

ICAO Type Designator
B744

Airport ICAO Code
NZAA

This article is published under license from Avherald.com. © of text by Avherald.com.
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