Description

On 22 December 2013, a Boeing 747-400 (G-BNLL) being operated by British Airways on a scheduled passenger flight from Johannesburg to London Heathrow was taxiing for departure at night in normal ground visibility when the aircraft was involved in a collision with a building adjacent to the taxiway. Substantial damage to both aircraft and building resulted and a significant fuel leak occurred. The aircraft occupants were all uninjured but four people in the building sustained minor injuries.

Investigation

An Investigation was carried out by the South African CAA Accident and Investigation Division (AAID). Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) data was successfully downloaded to assist but it was noted that the parameters recorded by the FDR did not include some, such as applied brake pressure, which would have been useful.

It was established that the flight crew consisted of the Captain, a First Officer who was designated PF for the departure and a Senior First Officer (SFO) who was an augmenting crew member carried to facilitate cruise relief for the operating crew. The SFO was occupying a supernumerary crew seat in the flight deck in accordance with Company Standard Operating Procedures (SOPs). All three crew members were familiar with the airport through multiple previous visits and all had significant experience on the 747-400 aircraft type. A pre flight brief lasting around 7 minutes was conducted prior to push back which included the expectation that the taxi routing they would get for departure runway 03 would be via taxiway 'A'.

When the clearance came it was not the one briefed but the alternative of proceeding to runway 03L via taxiway 'B'. No revision to the earlier crew brief took place. Initially, the clearance as correctly read back was followed but, when taxiway 'B' turned to the left as it approached the runway Cat 2 holding point which was the clearance limit, the aircraft wrongly continued straight ahead on a narrower taxiway 'M' which unlike 'B' had no centreline lighting. It was found that as soon as the aircraft entered 'M', the First Officer expressed his doubts about the apparent narrowness of the taxiway (it was actually only 18 metres wide compared to the 30 metre width of 'B') but there was no response from either of his colleagues and he continued ahead. His remark about the width were suspected by the Investigation to have been triggered by the transition from the green taxiway centreline lighting on 'B' to only the blue edges along 'M'.

Then, with the aircraft taxi speed at about 14 knots, a further remark by the First Officer when the aircraft was about 10 metres from the building to the right of the taxiway with which it was about to collide that "that wing is not very far from that (building)", was followed almost immediately by impact of the right wing with the eastern side of the building, cutting through the second floor and completely demolishing the upper eastern side. The severity of the impact caused substantial structural damage to the wing and the cabin crew observed fuel beginning to flow from the wing and reported this to the flight crew.

Just prior to the collision, when he was unable to see the aircraft on taxiway 'B', TWR controller checked the Advanced Surface Movement Guidance and Control System display and discovered that the aircraft was on 'M' and heading towards the 'M' Apron. He immediately transmitted to the aircraft to "hold position" but by this time, the collision had already occurred and ATC had not yet been advised of it. No call by the aircraft to ATC reporting the collision was initially made and even subsequently, no “emergency” was declared. Only after ATC had instructed them to hold position did the Captain reply six seconds later that "we actually hit something here, standby please". No additional information was reported to ATC to explain what had happened. On the basis of this transmission from the aircraft and in the absence of further information, ATC instructed an Airport Rescue and Fire Fighting Service (ARFF) vehicle in the vicinity to go and "assist" the aircraft. Once the crew of this vehicle had appraised ATC of the situation, the crash alarm was activated to dispatch ARFF Tenders to the scene.

Three Tenders arrived and "reported observing a very large substantial quantity of fuel leaking from the damaged wing" but that the aircraft was "otherwise intact". At this point, all engines were still running. The Captain of the aircraft had already determined that it would be safer to disembark passengers normally rather than risking injuries with an (emergency) evacuation.

The substantial damage to the affected building, where four occupants had sustained minor injuries, required that the electrical supply be switched off. Only after this had been done, and the aircraft Captain had agreed to an ARFF request to shut down the engines and achieved this once the APU had been started, were the ARFF able to begin containing the fire risk posed by the fuel spillage by foam application. Some 37 minutes after the collision had occurred, the fuel spillage had been contained. An airstairs vehicle and buses had by now arrived and the occupants disembarked via door 5L for transportation back to the Terminal Building.

Whilst the ARFF was dealing with the fuel spillage, the Investigation noted that the CVR recorded crew conversation about the sequence of events leading to the collision. This included the First Officer saying “I saw it. It just didn’t look right. I wish I’d stopped. It just didn’t look right. It looked too close. I didn’t pick up the fact…I was looking for it to go straight. I didn’t see any turn off toward the end”. It was concluded that "through lack of situational awareness he could not make sense of or understand the events unfolding and was therefore unable to make the right decision to stop" and noted that as the junction between the 'B' and 'M' taxiways approached, the crew has just completed before take-off checks so that "his mind was focused on the objective of getting to the runway".

The Investigation found that the pre-departure crew briefing had used only the aerodrome overview chart and not also the text page which contained information on taxi details and cautions which included a caution note specifically on the potential for confusion at the junction of taxiways 'B' and 'M'. It was noted that an almost identical incident to the one being investigated but with the aircraft stopping on taxiway 'M' before reaching the building had occurred to another British Airways 747 in 2005 but had not been reported to either the South African CAA or its AAID. Whilst this failure to report had been in contravention of State regulations, it was accepted that corrective action to improve ground movement navigation aids and installation of A-SMGCS had followed.

The crew report that not all the taxiway lighting on taxiway 'B', and specifically some of the centreline lights, had been illuminated was investigated and it was found that a total of seven of the installed green centreline lights were not lit, five in the section from the apron after the curve leading to taxiway Bravo and two on the curve leading to the runway 03 Cat 2 holding point. It was also noted that over a distance of approximately 300 metres up to the holding point, no centreline lights were installed. It was also determined that the direction information sign on the left side of taxiway 'B' ahead of the intersection of 'B' and 'M' which consisted of a black inscription on a yellow background was not lit but was supposed to be. In respect of the installed but unlit centreline lights, it was found that, on the night in question, the absence of some illuminated lights had been due to maintenance activity. However, the Investigation could find no evidence that the required Notice To Airmen had been issued.

Issues relating to the designation, lighting installation, lighting activation and marking of adjacent obstructions in respect of taxiway 'M' were also identified. However, it was found that the Airside Safety Committee had not discussed these issues and their relevance to the hazards of the 'B' and 'M' intersection and that the airport operator, the Airports Company of South Africa (ACSA), had not included "the issue of aircraft (ground) movements and visual aids" as one of their top 20 hazards despite the 2005 incident.

Relevant British Airways SOPs were reviewed and it was noted that the failure of the crew to familiarise themselves with the actual taxi route once it became known was contrary to their requirements. In addition, although the relevant taxi chart was displayed by at least one pilot as required so as "to ensure correct interpretation of ATC requirements, to monitor taxi progress and to achieve general situational awareness", it was concluded that it had not been referred to at any time whilst taxiing.

It was also noted that although the British Airways Route Information Manual (Part C of the Operations Manual) contained an aerodrome brief for Johannesburg, the airfield and parking paragraph made no reference to any taxiway hazards.

The fact that the engines were still running when ARFF personnel arrived at the scene was reviewed and the Captain’s explanation that the engines had been left running so as to power the electrical system and keep the cabin lights on and prevent the passengers from panicking was noted. It was, however, considered that "it would have been better if they had used the APU and shut down the engines" because "the fuel spillage was a fire risk due to its volatility (and) keeping the engines running, particularly with the (high) exhaust temperatures in close proximity to the fuel, was considered to be a hazard".

The Investigation formally identified the Probable Cause of the accident as "the loss of situational awareness caused the crew to taxi straight ahead on the wrong path, crossing the intersection/junction of Bravo and Mike instead of following Bravo where it turns off to the right and leads to the Category 2 holding point. Following aircraft stand taxilane Mike; they collided with a building on the right-hand side of Mike".

Six Contributory Factors were identified as follows:

• Failure of the crew to carry out a briefing after they had received instruction from ATC that the taxi route would be taxiway Bravo.

• The lack of appropriate knowledge about the taxiway Bravo layout and relevant information (caution notes) on threats or risks to look out for while taxiing on taxiway Bravo en route to the Cat 2 holding point.

• The aerodrome infrastructure problems (i.e. ground movement navigation aids anomalies), which created a sense of confusion during the taxi.

• Loss of situation awareness inside the cockpit causing the crew not to detect critical cues of events as they were gradually unfolding in front of them.

• Failure of the other crew members to respond adequately when the Co-pilot was commenting on the cues (i.e. narrowness and proximity to the building).

• The intersection/junction of Bravo and Mike not being identified as a hotspot area on the charts.

A total of ten Safety Recommendations were made as a result of the Investigation as follows:

• that the (UK) AAIB enter into consultations with the operator (British Airways) about the crew’s non-adherence to applicable briefing and taxi policies, procedures and requirements. The AAIB to communicate to AIID what the appropriate corrective action shall be to prevent recurrence.

• that the South African CAA should intensify the ramp inspections on all foreign operators to South Africa to ensure that they comply with international air operation standards, recommended practices and regulatory requirements in terms of the matters raised (i.e. availability and validity of aircraft documentation) wherever their destination in South Africa. The SACAA should also ensure that they put in place a proper, effective and efficiently system of traceability in this regard.

• that the (UK) AAIB look into or address the matter of the revision status of the aeronautical data issued by the third party service provider referencing the issues raised of (British Airways contracted service provider) Navtech. It should be noted that the South African AIP is a legal document prepared in accordance with the Standards and Recommended Practices (SARPs) of ICAO Annex 15 of which the charts contained in it are produced in accordance with ICAO Annex 4. Its purpose is to provide appropriate safety information (i.e. aeronautical data) to the aviation industry; therefore operators are to ensure that the aeronautical data they use, irrespective of the source, complies with the information published in the South African AIP.

• that the South African CAA should finalise the commitments made to ICAO concerning the SACAA aeronautical information service (AIS) safety oversight responsibility over service providers, so that situations similar to the one of Navtech will not recur in South Africa.

• that the South African CAA should consult with the Airports Company of South Africa (ACSA) about the inadequacies of the ground movement infrastructure issue (e.g. taxiway centreline green lights and signage) identified on Bravo, which may include other taxiways and/or runways at Johannesburg. It is important to point out that the infrastructure inadequacies identified there caused confusion which could have been prevented with proper maintenance and/or infrastructure development.

• that the South African CAA should intensify the safety oversight inspections over ACSA operations relevant to the integrity of the airport infrastructure (e.g. lights and signs) with the aim to completely prevent the recurrence of non-compliance by ACSA with quality processes.

• that the Airports Company of South Africa (ACSA) should consider complete removal of the building into which the British Airways aircraft collided, as in future it will continue to pose a safety risk to crews taxiing on taxiway Bravo en route to the Cat 2 holding point. This recommendation is made based on the evidence of the (British Airways Air Safety Report) ASR Ref:24674 incident during April 2005 when the aircraft stopped short of colliding with the building, followed by this accident Ref:CA18/2/3/9257 on the day in question.

• that the South African CAA should consult with (the UK) AAIB about the British Airways flight crew’s non-compliance with the clear and unambiguous taxi instructions, which were to push back facing south using Bravo to Category 2 holding point for take-off from Runway 03L and not what they actually did, which was to taxi full length to end of the taxiway.

• that 'the South African CAA should consult with the (UK) AAIB about the British Airways flight crew’s action in that they did not comply with the SOP requirement that they should immediately have stopped when in doubt about the conditions on taxiway Bravo during the taxi phase.

• that the South African CAA should consult with (ANSP) Air Traffic and Navigation Services (ATNS) about their plans to fully commission the A-SMGCS system. This will ensure that the identified radar system is integrated completely with ATNS’s quality control process to effectively and efficiently carry out surveillance over ground movement areas. The aim is to contribute to the safety and efficiency of aerodrome surface movement control during low visibility operations (LVOs), e.g. at night, especially to provide active alerts to controllers as a means of early warning of potential incursions and/or taxiing into unsafe locations.

The Final Report was published in June 2015.

Further Reading

• Aerodrome Lighting
• Taxiway Lighting
• Situational Awareness
• Continuation Bias
• Cross-checking Process
• Crew Resource Management
• Line Oriented Flight Training