A35K, London Heathrow UK, 2022
A35K, London Heathrow UK, 2022
On 2 January 2022, an Airbus A350-1000 floated during the landing flare at London Heathrow and when a go-around was commenced, a tail strike accompanied main landing gear runway contact. A subsequent further approach during which the Captain took over as handling pilot was completed uneventfully. The Investigation attributed the tailstrike to a full pitch up input made simultaneously with the selection of maximum thrust when very close to the runway surface, noting that although the initial touchdown had been just beyond the touchdown zone, 2,760 metres of runway remained ahead when the go around decision was made.
On 2 January 2022, an Airbus A350-1000 (G-XWBC) being operated by British Airways on a scheduled international passenger flight from Dubai to London Heathrow sustained a tailstrike as it commenced a go around from the landing flare at destination in day VMC and unexceptional surface wind conditions. A second approach to a normal landing was subsequently completed but significant damage was subsequently found to the underside of the rear fuselage.
A Field Investigation was carried by the UK Air Accident Investigation Branch (AAIB). The FDR and CVR were removed from the aircraft and their data successfully downloaded. It was noted that the 49 year-old Captain had a total of 17,305 hours flying experience which included 652 hours on type. The total and on-type experience of the First Officer who was acting as PF during the first approach and go around was not recorded.
The flight, including the first approach until just prior to touchdown, was confirmed to have been entirely normal. The approach briefing noted the TAF valid for the expected arrival time gave a mean surface wind of 230°/12 knots with TEMPO (temporary) 220° 20-30 knots in any heavy showers. The expected landing runway, 27L had a 3,658 metre LDA and a 900 metre TDZ marked with six pairs of painted stripes. In accordance with the operator’s Monitored Approach SOP, although the Captain was acting as PF en route, the final stages of the destination approach would involve the First Officer taking over for the final stage of the approach and the landing. The briefing was based on landing performance calculations for both Flap 3 and Flap Full and although only medium to poor braking action was assumed due to the possibility of a wet runway surface, the autobrake BTV (Brake-to-Vacate) option was available and was set to allow the runway to be vacated via the N6 RET.
The ATIS wind during the approach was 210° 11-22 knots. The First Officer took over as PF at approximately 1000 feet agl and the AP was subsequently disconnected at approximately 400 feet. FDR data showed that as the aircraft continued descent below 100 feet agl, it was stable and 2°/3° nose up with an 800 fpm descent rate. At approximately 55 feet agl, the aircraft was flared and shortly afterwards the thrust was set to idle - it was noted that according to the FCTM, the flare height would normally be approximately 40 feet agl but this was qualified by adding that this would “vary according to the effect of operational conditions which directly affect the rate of descent”.
Over the following three seconds as the aircraft descended through 10 feet agl, more nose-up pitch input was made to achieve around 6° nose-up. The aircraft continued level at 5 feet agl which triggered a corresponding audio callout but it did not touch down and after a second such callout, the Captain called “go-around”. At this point, the aircraft was approaching the end of the TDZ although 2,760 m of runway still remained ahead of the aircraft (see the illustration below).
Part of the aerodrome chart showing the landing runway and the intended exit point. [Reproduced from the Official Report]
The First Officer selected TOGA thrust levers and simultaneously made a pitch up input which reached the maximum of 15° nose up as the aircraft briefly touched down firmly. The Captain subsequently stated that he had felt that this initial pitch up was excessive but that by the time he could have reacted, the First Officer had “already begun taking corrective action”.
The nose-up pitch input was reduced although the achieved pitch attitude, which had increased rapidly, was approaching 10º nose up whilst the airspeed had significantly decreased as the engines continued to spool up. The aircraft briefly touched down before becoming airborne again as the airspeed reached a minimum of 135 knots and the tailstrike occurred. A maximum achieved pitch attitude of 16° nose-up was recorded before the reduction in pitch up input began to take effect and the aircraft then became airborne and climbed away into a normal go-around. Passing 400 feet agl, an ECAM tailstrike warning was annunciated and the TWR controller advised that a tailstrike had been observed.
With runway 27L temporarily out of use because of the need for a runway inspection, positioning for a landing on runway 27R was accepted with the First Officer initially continuing as PF before the Captain took over for an uneventful landing. On clearing the runway, the airport RFFS carried out an external damage inspection after which the aircraft was taxied to the allocated gate and shut down. A damage assessment identified two areas of damaged skin on the rear lower fuselage, in one of which there had been abrasion of the paint, copper mesh lightning protection layer and up to three carbon fibre reinforced plastic layers. The toilet waste panel was found to be damaged beyond repair as its abraded leading and trailing edges had thinned the material and thus compromised the strength of the panel. Also, three vent pipes positioned along the rear of the fuselage were found to have been bent and abraded by ground contact and had to be replaced.
Rear lower fuselage damage to the skin, toilet waste panel and tailstrike sensor. [Reproduced from the Official Report]
Why It Happened
The Captain ordered a go around because he assessed that a touchdown would not be achieved within the TDZ. This meant that in accordance with the OM Part ‘A’ applicable to all fleets, the direction “the aircraft is still airborne at the end of the TDZ, or it is obvious that the landing will not be within the TDZ, a rejected landing shall be initiated” was applicable and the PM must call “go around” as happened in this case. This requirement was contained in a section of the Manual aimed at preventing runway excursions described as ‘Safe Touchdown Criteria’. This policy was followed by the information that “if a landing is made beyond the TDZ then it would be recorded as an OFDM event” and any landing beyond the TDZ would be expected to raise a corresponding ASR. The operator advised the Investigation that any such occurrence “would be investigated with the crew to understand the event and give guidance to prevent recurrence (noting that) their A350 fleet operates to runways with landing distances as short as 2,400 metres”.
For a go around initiated close to the runway, the FCTM was found to state that an excessive rotation rate should be avoided in order to prevent a tailstrike whilst noting that a temporary main landing gear contact with the runway “is acceptable”. It was also noted that during manual landings with the aircraft less than 50 feet agl, an aural alert is triggered if the pitch attitude is expected to exceed 9° nose-up using a predictive calculation of the pitch attitude one second ahead. It was also noted that below 400 feet agl with a landing imminent, a fixed tailstrike pitch limit of 8.6° is displayed on the PFD based on “the pitch limit on the ground with the main landing gear compressed plus an additional margin”.
The maximum nose up pitch input made by the First Officer at the same time as selecting TOGA thrust with the aircraft so close to the runway failed to take account of the fact that engine spool up time was such that effective thrust to arrest descent with the airspeed dropping was not going to be available in time to prevent a main landing gear runway contact with the achieved pitch attitude in excess of 9°. Indeed, it had already reached a recorded 11° as the tailstrike began and had continued increasing and was passing 13° when the tailstrike ceased as the main landing gear became fully airborne.
The formally-stated Conclusion of the Investigation was as follows:
A go around was initiated from low height and low speed. The aircraft had insufficient energy to climb immediately and so touched down during the go-around process. The pitch rate induced by the co-pilot caused the aircraft to reach a nose up attitude sufficient to cause a tailstrike as the aircraft touched down.
The Final Report was published on 18 August 2022. No Safety Recommendations were made.