B773 / B752, London Heathrow UK, 2022

B773 / B752, London Heathrow UK, 2022

Summary

On 28 September 2022, a Boeing 777-300 taxiing for departure at London Heathrow was in collision with an arriving Boeing 757 which had turned onto its assigned gate prior to the stand entry guidance system being available without informing ATC. The 757 was taxiing as cleared following the illuminated taxiway centreline lighting. The airport AIP entry was found to state that in the absence of stand entry guidance, aircraft must remain on the taxiway centreline. The Investigation noted that lack of stand entry guidance is a common occurrence at this airport and needs to be addressed by all those involved.

Event Details
When
28/09/2022
Event Type
GND, HF
Day/Night
Night
Flight Conditions
On Ground - Normal Visibility
Flight Details
Operator
Type of Flight
Public Transport (Passenger)
Flight Origin
Intended Destination
Take-off Commenced
No
Flight Airborne
No
Flight Completed
No
Phase of Flight
Taxi
Flight Details
Operator
Type of Flight
Public Transport (Passenger)
Flight Origin
Intended Destination
Flight Completed
Yes
Phase of Flight
Standing
Location - Airport
Airport
General
Tag(s)
Aircraft-aircraft collision, CVR overwritten
HF
Tag(s)
Procedural non compliance
GND
Tag(s)
On gate collision, Aircraft / Aircraft conflict, Wingtip clearance
Outcome
Damage or injury
Yes
Aircraft damage
Minor
Non-aircraft damage
No
Non-occupant Casualties
No
Occupant Injuries
None
Off Airport Landing
No
Ditching
No
Causal Factor Group(s)
Group(s)
Aircraft Operation
Airport Operation
Safety Recommendation(s)
Group(s)
None Made
Investigation Type
Type
Independent

Description

On 28 September 2022, a Boeing 777-300ER (HL-7782) being operated by Korean Air on a scheduled international passenger flight from London Heathrow to Seoul as KE908 was taxiing for departure past a nose-in gate occupied by a Boeing 757-200 (TF-FIK) being operated by Icelandair on a scheduled international passenger flight from Reykjavik to London Heathrow as FI454 which was not fully parked in normal night visibility when its right wing tip struck the rudder of the stationary 757 causing damage to both aircraft but no injuries to the occupants. 

Investigation

An Accident Investigation was carried out by the UK AAIB. The CVR and FDR from both aircraft were downloaded but the 777 CVR had not been isolated and relevant data from it were found to have been overwritten. Useful data was obtained from the other three recorders and relevant airport CCTV and airport operator vehicle dashcam recordings were also available as was a recording of transmissions on the GND radio frequency whilst the 757 was waiting to complete its parking.

The Captain of the Boeing 777 was found to have a total of 10,561 hours flying experience of which 3,384 hours were on type and its First Officer had a total of 3,478 hours flying experience of which 2,735 hours were on type. The Captain of the Boeing 757 reported having a total of 15,500 hours flying experience of which 12,500 hours were on type and its First Officer had a total of 2,907 hours flying experience of which 2,321 hours were on type. 

What Happened

The 757 Captain stated that only after he had turned the aircraft onto the assigned nose-in stand centreline at Terminal 2B did he see that the Visual Docking Guidance System (VDGS) was not on. He therefore brought his aircraft to a stop approximately 20 metres from the anticipated final parking position. A radio query to the ground handling agent on when the VDGS would be activated received the response that “marshallers were aware of their arrival and would be there very shortly”. The crew did not inform the ATC GND controller that they were not fully parked contrary to requirements contained in the EGLL AIP entry which required aircraft to remain on the taxiway centreline if the VDGS was not switched on which the Captain stated he was aware of. 

Part of the UK AIP entry on stand entry guidance at Heathrow is reproduced from the Official Report below:

Flight crew must not attempt to self-park if the VDGS is not activated or calibrated for their aircraft type.

In the event of there being no activated VDGS displayed upon approach to the stand, flight crew should: 

-    Hold position on the taxiway centre-line.

-    Inform Ground Movement Control (GMC) they are awaiting stand entry guidance.

-    Contact company to arrange activation. 

Concurrently with the 757 taxiing in, a Boeing 777-300 was taxiing from the southside Terminal 4 for takeoff on Runway 27R. Having crossed runway 27L, it was then cleared to “follow the green lights and hold at Titan” which took the aircraft along the parallel taxiway ‘A’ before turning left onto taxiway ‘L’ which led towards the runway 27R holding points. As it made this left turn, the First Officer saw the 757 on Stand 241 and told the Captain that “it looked like it was protruding from the stand”. The Captain looked at the 757 but as he could not see an anti-collision light, he assumed that it was fully parked and although he thought it was “quite close”, as ATC had not mentioned a conflict, he decided it was safe to taxi past. He reduced speed slightly and deviated slightly to the right of the taxiway centreline before returning to it and continuing to taxi unaware that a collision had occurred.

As the 777 passed behind, the crew of the 757, which by then had been stationary for six minutes, felt a “sudden jolt”. The 757 First Officer looked out of his window and saw the 777 taxiing past and both 757 pilots realised there had been a collision. The Captain called the rear cabin crew on the interphone and was advised that “they had felt the jolt but they were fine and no one had been injured”. The Captain then informed the GND controller that they “thought there had been a collision”. The 777 crew had not realised there had been a collision and were continued north on taxiway ‘L’ until they were so informed by GND and instructed to hold position. As this exchange was taking place, one of the 777 passengers told the cabin crew that they had seen the left wingtip hit another aircraft and the Captain was advised of this at about the same time as GND instructed them to stop. The position of the two aircraft when they collided is shown in the illustration below.

B773 B752 LHR 2022 positions on collision

The position of the two aircraft when they collided. [Reproduced from the Official Report]

Just prior to the collision, the marshaller assigned to the 757 had arrived on the stand and had seen the 777 passing behind but did not realise there had been a collision and “switched on the VDGS at about the same time as the collision occurred". Once the 757 Captain had confirmed he was content to complete the taxi onto the stand, the aircraft was marshalled forwards to its final parking position and its passengers were disembarked normally. The 777 was shut down on the taxiway and its passengers were disembarked to buses and taken to their boarding terminal. Damage was confirmed to both aircraft (see the illustrations below). 

B773 B752 LHR 2022 777 wingtip dmg

Damage to the 777 wingtip viewed from below. [Reproduced from the Official Report] 

B773 B752 LHR 2022 777 wingtip dmg 2.jpg

Damage to the 777 wingtip viewed from above. [Reproduced from the Official Report]

B773 B752 LHR 2022 757 dmg

Damage to the 757 vertical stabiliser. [Reproduced from the Official Report] 

The Context  

On the day of the accident, one of the tunnels used to access the central area at Heathrow had been closed for several hours which resulted in delays due to two way traffic in the other tunnel. The 757 ground handling agent reported that these delays had resulted in several of their staff taking longer than usual to get to work. Due to consequent staff shortage, they had realised that provision of a dispatcher for the 757 arrival would be delayed and noted that this person’s duties included activating the stand entry guidance. The handling agent stated that they had reached an agreement with the airport operator that in these circumstances, they would provide a marshaller as an alternative to activation of the guidance system. The airport operator had eventually assigned this task to one of its leader vehicle drivers, who had driven to the stand on which the 757 was waiting “as soon as he had completed his previous task, arriving just prior to the collision”. However, the airport operator stated that there were no such agreements to provide marshallers in the event of staff shortages at any handling agent and that “it would only expect to provide a marshaller in the event of a failure of the guidance system as specified in the UK AIP entry for Heathrow”. The airport operator believed that as “other access points were available to staff, the tunnel closure should not have caused any staff to be delayed”

In respect of the 757 crew not informing ATC that they were not fully parked, the Captain stated that his normal practice was to initiate the turn onto the stand before looking to see if the guidance was activated rather than looking sideways for guidance whilst still on the centreline despite awareness of the Heathrow-specific requirement and added that “in his experience, the guidance was often switched on as the aircraft turns onto the stand and that starting the turn had never been a problem, nor had he heard of it being a problem for other pilots”. He claimed that “he had considered informing ATC that they were not fully parked, but the ground frequency was too congested and it was not possible for them to make a radio call”.

In respect of the latter statement, a review of radio transmissions on the GND frequency during the time the aircraft was stationary found that from soon after they stopped, “there were several periods of between 5 and 7 seconds duration when there was no transmission with the longest gap during the 6 minutes stationary time being 18 seconds". A review of the 757 CVR data during the time the aircraft was stationary on stand also “did not reveal any attempt to contact the ATC ground frequency or any crew discussion about contacting them until after the collision”.     

It was also found during the Investigation that during a 16 minute period around the time of the investigated accident, five other aircraft had been unable to park because no stand entry guidance was available but “they had all been reported to ATC in accordance with the AIP” and the circumstances were therefore not hazardous. It was noted that both the ANSP and the airport operator accepted that lack of stand guidance was “currently a persistent problem”.

A Previous Similar Event

It was noted that the AAIB had become aware of a similar unreported ground collision event at Heathrow which had occurred some six weeks prior to this one in which a departing Boeing 787-8 had collided with an arriving Boeing 787-9 which had also turned onto stand and stopped before being fully parked to await marshalling. In this case, damage to the departing aircraft was not found until after it had completed its flight.

Safety Action taken as a result of this accident by the Heathrow ANSP was noted to have included the issue of a ‘Safety Alert’ to remind operators about the AIP entry regarding VDGS. This Alert was subsequently highlighted at the Heathrow Flight Operations Safety Committee and in several other forums.

The Conclusion of the Investigation was formally recorded as:

The collision occurred because the commander of the B777 continued to taxi past the protruding B757, believing it was fully parked and that the ATC clearance and green taxiway lights implied the route was clear. The commander of the B757 did not follow the Heathrow AIP instruction to remain on the centreline if no stand guidance is available, because his normal practice was to look for guidance after he had turned onto the stand. 

The initiating event was a lack of stand guidance when the B757 arrived on stand, caused by ground staff shortages. Lack of stand guidance is a common occurrence at Heathrow that all parties should continue to work together to address.  

The Final Report was published on 8 June 2023. No Safety Recommendations were made.

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