On 21 January 2010, a Boeing 744-400F being operated by Cargolux on a scheduled cargo flight from Barcelona to Luxembourg was about to make a daylight touchdown following a ILS Cat 3B approach to runway 24 at destination in thick fog when one of the pilots briefly saw an object which he believed to be a vehicle stationary within the TDZ not far from the centreline. It was subsequently found that one wheel of the right body landing gear had struck and damaged the roof of a van being used by a maintenance crew carrying out preventive maintenance on the runway centreline lights. The only damage to the aircraft was to the tyre on the wheel which hit the vehicle which had to be replaced.
An Investigation in accordance with International Civil Aviation Organisation (ICAO) Annex 13 provisions was carried out by the AET - the Administration of Technical Investigations within the Department of Transport of the Luxembourg Ministry of Sustainable Development and Infrastructure.
All relevant recordings, including the aircraft Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR), were available to the Investigation, although it was noted that the airport did not have Surface Movement Radar or any other means of non visual ground traffic surveillance, recorded or otherwise.
It was found that, as required, LVP had been in force at the time of the occurrence and had been so for several hours due to thick fog. The IRVR at the time of the landing was in the range 250 metres to 350 metres and the applicable DH for landing had been 17 feet above reference threshold elevation (arte). The height of the roof of the van involved was measured at 2.54 metres and it was found to have been positioned some 340 metres from the runway threshold and slightly to the right of the centreline. The two men working on the lighting, an electrician and his assistant, had run from the runway upon hearing the sound of an approaching aircraft.
The maintenance van involved was found to have had a radio with loudspeaker on the TWR frequency and the electrician had a mobile phone and the TWR contact number but the TWR did not have the number of the mobile phone being carried. Routine communication between TWR and the maintenance crew was carried out on GND frequency 121.90 MHz, a frequency which was not published in the AIPs or on the aerodrome navigation charts.
Twenty minutes prior to the time of the occurrence, the maintenance van had been cleared to enter the runway by ATC and there had been no further radio communication between the van and ATC. It was found that the log file for the TWR Aerodrome Data Display (ADD) did not show any corresponding activation of the ‘runway blocked’ function in connection with this clearance to enter the runway although it did show that it had been used shortly after the collision in connection with another vehicle entering the runway to look for debris created by it. However, it was found that the ADD had been under evaluation at the time of the occurrence and did not have operational status. The decision on whether or not to use it had been left to the controllers on duty.
It was calculated that because of the nose up attitude of the aircraft as the automated landing flare occurred, the flight crew would have had no sight of the van for a horizontal distance of almost 30 metres before the impact occurred and neither crew member reported being aware of any impact.
In respect of ATC practices, it was found that a number of existing provisions in the MATS had not been applied and that common practices which were applied by controllers were not documented in the MATS. The Investigation also found cause for concern in respect of the actions of ATC in the aftermath of the occurrence. It was found that a failure by the TWR to properly disseminate information to other involved parties, in particular Approach, Rescue and Fire Fighting Services and Airport Operations, had led to confusion and a partial loss of necessary situational awareness. For example, in LVP, an inbound flight was instructed to continue approach after reporting 8 nm final whilst another aircraft remained lined-up on the runway as the Rescue and Fire Fighting Services located and removed debris, and at no point was the runway formally closed.
Relevant content of the ICAO Annexes was noted, including a Recommendation in Annex 14 Volume 1 that “surface movement radar for the manoeuvring area should be provided at an aerodrome intended for use in runway visual range conditions less than a value of 350 metres”. Various more detailed recommended procedures contained in the ICAO ‘Manual on the Prevention of Runway Incursions’ (ICAO Doc 9870) and the EAPPRI were also noted.
The formal statement of Causal and Contributory Factors resulting from the Investigation was as follows:
- The impaired operational readiness of the (Electrical) department due to a manning shortcoming, combined with the lack of provisions to appoint external workforce if necessary, prevented (the ANSP) ANA from scheduling preventive maintenance work outside of normal operating hours;
- The decision to carry out preventive maintenance work in low visibility conditions without hampering air traffic gave priority to flight operations over safety aspects;
- The lack of adequate co-ordination between aerodrome control tower and (the Electrical) department with regard to the preventive maintenance work contributed to a reduced situational and organisational awareness of the TWR control staff;
- Inadequate procedures for the access of vehicles to the RWY and ILS sensitive area during LVP contributed to the development of an unsafe condition;
- Read-back procedures were not adequately applied by aerodrome control tower on ground control frequency, making this procedural safety net ineffective;
- Low visibility weather conditions, associated with the lack of supplementary ground traffic control and surveillance equipment, limited the capability of aerodrome control tower to identify and correct a developing unsafe condition;
- The use of different frequencies for air traffic and ground traffic on the manoeuvring area reduced the situational awareness of (the) maintenance crew working on the RWY, preventing them from taking avoiding action.
Safety Action taken since the event was noted to have included amendment to the MATS to restrict access to the ILS sensitive area when LVP are in force. However it was also noted that, although a tender for the implementation of an Advanced Surface Movement Guidance and Control System Level 2 at Luxembourg Airport had been issued in 2010, by the time the Investigation was concluded two years later, there had yet to be an award of such a contract and that “the implementation process is still on hold”.
Twelve Safety Recommendations were issued as a result of the Investigation as follows:
- that ANA (the ANSP) should establish appropriate supervisory means to ensure the correct application of standard phraseology procedures by ATCO’s. [LU-AC-2012/001]
- that ANA (the ANSP) should implement the recommendation by the International Civil Aviation Organization (ICAO) in Annex 11 Air Traffic Services, paragraph 3.3.3. stating that: ‘air traffic control units should be equipped with devices that record background communication and the aural environment at air traffic controller work stations, capable of retaining the information recorded during at least the last twenty-four hours of operation.’ [LU-AC-2012/002]
- that ANA (the ANSP) should provide the aerodrome control tower with supplementary means of control and surveillance of ground traffic in accordance with the specifications for an A-SMGCS Level 2 implementation. [LU-AC-2012/003]
- that ANA (the ANSP) should conduct all communications associated with the operation of the runway on the same frequency as utilized for the take-off and landing of aircraft and all communications associated with the operation of the taxiways should be conducted on a different designated frequency. [LU-AC-2012/004]
- that ANA (the ANSP) should ensure that all communications associated with the operation of the runway and the taxiways are conducted in standard aviation English and in accordance with ICAO language requirements for air-ground radiotelephony communications. [LU-AC-2012/005]
- that ANA (the ANSP) should amend work procedures for the access to the manoeuvring area during LVP:
- to establish the operational need for all access of vehicles and personnel to the manoeuvring area;
- to ensure an appropriate co-ordination between ATC and operators on the manoeuvring area. [LU-AC-2012/006]
- that ANA (the ANSP) should review the Safety Management System (SMS) to ensure an effective safety assessment of tasks which may affect the safety of airport operations. [LU-AC-2012/007]
- that ANA (the ANSP) should provide adequate operational means (manpower & equipment) to (the electricians) department to ensure an appropriate level of operational readiness for aerodrome operations. [LU-AC-2012/008]
- that ANA (the ANSP) should review the MATS to ensure that common practices and local instructions are contained in MATS and that they are not in contradiction with prevailing MATS provisions. [LU-AC-2012/009]
- that ANA (the ANSP) should establish written instructions in the MATS and supervise their operational implementation to ensure the clear and unambiguous marking of a temporarily occupied runway by aerodrome control tower on all active work positions. The information on RWY occupation should also be provided to approach control to enhance operational awareness. [LU-AC-2012/010]
- that ANA (the ANSP) and the Luxembourg Airport Authority should review the emergency response plan and inform all concerned staff about the criticality of actions to be undertaken in the aftermath of safety occurrences with regard to:
- debris removal;
- staff response for alerting and co-ordinating with all interested parties;
- staff removal from position when involved in a safety occurrence;
- Critical Incident Stress Management (Critical Incident Stress Management). [LU-AC-2012/011]
- that ANA (the ANSP) should implement back-up communication means for ground operators on the manoeuvring area in low visibility conditions to maintain two-way communication with the aerodrome control tower in case of an R/T equipment failure and establish appropriate procedures to support the operational implementation. [LU-AC-2012/012]
The Final Report was published on 10 December 2012. Appendix ‘B’ to the Report is a tabulation which shows the findings of the investigation tabulated according to the Systemic Occurrence Analysis Methodology (SOAM) including ‘absent or failed barriers’. Relevant Safety Recommendations to address these are identified on the tabulation and against relevant Safety Recommendations.