YK-AHB hits catering loader at LHR

YK-AHB 747SP Syrianair

Engine hits catering loader

The aircraft YK-AHB (c/n: 21175) landed at Heathrow Airport and started taxiing to the stand. The handling agent's dispatcher had not arrived at stand R36 when the aircraft was ready to enter the stand. The electronic Stand Entry Guidance System (SEGS) was thus not switched on. The aircraft proceeded onto the stand, but was positioned towards the right side of the stand area. During the parking process, the outboard section of number 4 engine intake cowl contacted the upper front part of a catering loader. Examination of the position of the aircraft after the accident showed that the nose landing gear was on the centre line for stand R36R, instead of the correct R36 centre line. 

Aircraft Type and Registration: Boeing 747 SP-94, YK-AHB
No & Type of Engines: 4 Pratt & Whitney JT9D-7 turbofan engines
Year of Manufacture: 1976
Date & Time (UTC): 14 April 1996 at 0840 hrs
Location: Stand R36R, London Heathrow Airport
Type of Flight: Public Transport
Persons on Board: Crew - 13 Passengers - 155
Injuries: Crew - None; Passengers - None; Others - 1 (minor)

Nature of Damage: Damage to No 4 engine intake cowl
Commander's Licence: Airline Transport Pilot's Licence (Syria)
Commander's Age: N/K
Commander's Flying Experience: 21,147 hours (of which 3,504 were on type), Last 90 days - 109 hours, Last 28 days - 13 hours

Information Source: AAIB Field Investigation

The aircraft was operating a scheduled service route Damascus-Munich-Heathrow, landing on Heathrow's Runway 09L at 0836 hrs. Heathrow Ground Control instructed it to taxy via the outer taxiway, changing to the inner taxiway at block 21 and to park on stand R36, which was only a short distance away from the landing runway. The taxiing instructions were acknowledged by the flight crew. The handling agent's dispatcher had not arrived at Stand R36 by the time the aircraft was ready to enter the stand. The electronic Stand Entry Guidance System (SEGS) was thus not switched on.The aircraft proceeded onto the stand, but was positioned towards the right side of the stand area. During the parking process, the outboard section of the number 4 engine intake cowl contacted the upper front part of a catering loader vehicle which was correctly located within the inter-stand clearway area. The impact pushed the vehicle until it came into contact with a second catering vehicle positioned behind the first. The accident was observed by an Airside Operational Support Unit officer, who passed a radio message to ATC to advise the aircraft to shut down its engines immediately. The two occupants of the vehicles had been transferring catering items. They made a rapid egress during which one of them sustained minor laceration injuries. The aircraft's engines were shut down and the passengers deplaned normally.

Examination of the position of the aircraft after the accident showed that the nose landing gear was on the centre line for stand R36R, instead of the correct R36 centre line. The aircraft's wing tip and number 4 engine thus encroached across the inter-stand clearway between stands R36R and R38. The main landing gears were not equally straddled across the R36R centre line, being biased toward the central R36 stand.

The commander was familiar with operations into Heathrow Airport and the available SEGS, but R36 was not one of the stands normally used by the airline.

Stand Description, Identification and SEGS

Stand R36 is configured as a Multiple Aircraft Ramp System (MARS) stand, such that the central (main) stand may be occupied by one large aircraft, such as the B747. Alternatively, if required, two smaller aircraft may occupy the same stand area by use of additional centre lines provided at appropriate distances either side of the main stand centre. These additional centre line are identified by the alpha-numerics R36 Left (R36L) and R36 Right (R36R).The main centre line is marked with a continuous yellow paint line. The additional Left and Right centre lines are each painted with a continuous line, alternating white and yellow in colour. Only the central stand has an identifier plate at the head of the stand (marked R36).

The three centre lines (R36L, R36 and R36R) are identified by means of yellow identifiers painted on the taxiway surface. They are located adjacent to arrows pointing from the taxiway centre towards the appropriate stand centre line. The stand centre lines commence at the stand/taxiway boundary. There is thus a gap between the taxiway arrow and the start of the centre line. Repeater identifiers are painted on the surface at the start of the centre lines for R36L and R36R only.

Visibility from the flight deck of the Boeing 747 is such that the stand identifier markings on the taxiway and stand entrance would not have been visible once the aircraft had begun to enter the stand.

Centre line manoeuvring guidance is provided only for the central (main) stand by means of the Azimuth Guidance Nose-In Stands (AGNIS) light system. Stopping guidance is provided only for the main stand by means of a Parallax Aircraft Parking Aid (PAPA) board, located to the right side of the head of the stand. These systems are operated through an electronic timer, such that a ground handling agent is required to activate the system prior to the aircraft arriving to park on the stand. The subĀ­stands have no electronic parking guidance systems available in the case of R36L/R.

Aerodrome Information and Navigation Charts

During this investigation, four sets of documentation relating to the layout and nature of the parking stands at Heathrow was examined, namely:UK CAA Aeronautical Information Publication (AIP), Aerodromes (AGA) Section

Heathrow Airport Limited, Operational Safety Instructions (OSI)

Aerad Flight Guide, aerodrome charts for London Heathrow

Jeppesen Airway Manual, airport charts for London Heathrow

None of the documents examined contained any diagram indicating which stands are configured for the MARS system. The AIP entry, while making vague reference to the MARS concept, did not describe the layout of such stands in any detail. The current Heathrow OSI's did not contain any references or descriptions of the MARS system, although other aspects of SEGS were covered in detail.

The Aerad charts contained the most comprehensive description of the MARS system, correctly defining the centre line paint colours and AGNIS provision. The Jeppesen charts did not mention the presence of MARS stands at all and there were conflicting statements on different pages regarding the paint colour of the "normal" stand centrelines. However, Jeppesen correctly conveyed the content of a Heathrow OSI and highlighted the fact (in bold type) that 'on no account should aircrew attempt to self-park if the Stand Entry Guidance is Unserviceable, Uncalibrated or Not Switched On'. The chart library available to the flight crew involved in this accident included the Jeppesen chart containing this statement.

The commercial chart producers rely on information published in the AIP as a basis for the production of navigation charts. In turn, the information presented in the AIP is gathered from specific airport data. As a result of the apparent inconsistencies and omissions found during this investigation, both Heathrow Airport Limited and the CAA were advised by AAIB of the anomalies. The need for a comprehensive, accurate description to be made available for flight crews was also highlighted.

Heathrow Airport Limited indicated that a comprehensive OSI relating to all aspects of parking stands was in preparation and that its production would now be expedited. The CAA indicated that the approporiate aerodrome inspector would liaise with Heathrow Airport Limited to agree a suitable AIP revision. With these two improvements in hand, it was not deemed necessary to issue a formal Safety Recommendation.

Read Report.

Sourse: AAIB

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