On 12 November 1999, a French-registered ATR 42-300 being operated by Italian airline Si Fly on a passenger charter flight from Rome to Pristina was positioning for approach at destination in day Instrument Meteorological Conditions (IMC) when it hit terrain and was destroyed, killing all 24 occupants. A post crash fire broke out near the fuel tanks after the impact.
Since the place of occurrence was not a State but under direct UN jurisdiction, it was agreed that the Investigation under Annex 13 would be carried out by the French BEA acting for the State of Registration.
It was noted that Pristina Airport, elevation 1788 feet, had been re-opened after the cessation of military conflict only four months earlier. It was found that the accident aircraft had been chartered for public transport purposes by a UN World Food Program contractor who had sub contracted the provision of the service to the accident aircraft operator. Military ATC service was being provided to the accident aircraft at the time of the accident in accordance with established procedures in Kosovo at the time but the full detail of these procedures was not known to civil operators.
It was established that the aircraft, with the First Officer as PF, had struck a mountain with a summit of 4650 feet whilst in level flight at an altitude of 4600 ft QNH. It was found that at the time, it had been in receipt of radar vectors in an area to the north of the airport where the applicable SSA was 6900 feet and the minimum radar vectoring altitude was 7000 feet in preparation for an ILS approach to Runway 17. Although all airspace in and around Kosovo was defined as ‘tactical military airspace’, a Class ‘D’ airspace CTR was defined up to 5000 feet aal and radar control service was being provided. It was also established that although a GPWS/TAWS had been fitted, it had had an improperly documented history of faults and that during the accident flight, the aircraft had been flying with either an inoperative or an intentionally disconnected GPWS which the investigation considered that “the crew must have been aware of”. It was also noted that the emergency locator transmitter installed on board did not work after the accident.
The Investigation considered that:
“The conduct of the approach shows a clear lack of (flight crew) procedural discipline. (They) failed to check the aircraft’s track and the altitudes given by the ATC caused no comments although they were lower than the Minimum Sector Altitude on the approach chart used by Si Fly’s crews. This absence of comments is even more surprising given the fact that the operator did not, according to its Director of Operations, know the radar minimum safety altitudes at Pristina. The lack of procedural discipline is confirmed by the selection of a DH of 200 feet whereas the Operations Manual calls for a DH of 600 feet for this ILS. What is more, the crew also prepared an ILS approach without glide path, a procedure which is not authorised by the airline……this lack of procedural discipline and the passivity of the crew may be explained in part by the daily routine of these flights, but fatigue also appears to be a contributory factor. The study undertaken (by the investigation) did in fact show a high level of fatigue, in particular for the Captain. Moreover, note should also be made that this study did not take into account the concentration and workload, which the (recent) first flights, and difficult approaches to Pristina and Tirana had probably entailed. This state of fatigue promoted hypovigilance on the part of the crew, lulled by what appeared to be radar vectoring and made confident by the success of their previous approaches.”
It was also considered that there had been no evidence of “structured teamwork” by the flight crew during the accident flight with “imprecise preparation (for) the arrival, absence of callouts of safety altitudes or of the beginning of the procedure (and) absence of crosschecks.” The Investigation also failed to find any evidence of organised training for the flight crew on teamwork or on Crew Resource Management.
Further findings of the investigation included:
- that the event….shows (either) the crew’s lack of knowledge of its Operations Manual or (alternatively) the lack of importance they appeared to attach to respect for the instructions in this manual, at least with regard to flights conducted in a specific context, in this case that of humanitarian flights.”
- that the crew’s state of fatigue and its ignorance of the limits of radar vectoring at Pristina meant that they were unable to identify the critical situation in which they found themselves. It is likely that good teamwork and strict application of the Operations Manual would have avoided them being in this situation, left to their own devices.
- the great importance which must be given to aeronautical information, both in terms of quality and distribution. To be coherent and known to all, it must be written in the same format and be accessible through one channel. This is precisely the intention of the provisions of ICAO Annex 15.
- the aircraft operator was a recently created airline undergoing rapid development, thus in a financially weak position, having had no time to stabilise itself, or to acquire collective experience in its structures and procedures.
The Investigation concluded that the accident was due to:
- teamwork which lacked procedural discipline and vigilance during manoeuvres in a mountainous region with poor visibility.
- the aircraft being kept on its track and then forgotten by a military controller unused to the mountainous environment of the aerodrome and to preventing the risk of collisions with high ground, within the framework of the radar service he was providing.
- the operator's critical situation as a new company highly dependent on the lease contract, favouring a failure to respect procedures.
- the opening of the aerodrome to civil traffic without an advance evaluation of the operating conditions or of the conditions for distribution of aeronautical information.
It also found that the following factors contributed to the accident:
- crew fatigue, favouring a lowering of vigilance.
- undertaking the flight with an unserviceable or disconnected GPWS.
A number of Safety Recommendations were made as a result of the investigation. One was made early on to ensure that aspects of the accident circumstances that could affect the safety of continued civil transport operations at Pristina were addressed without delay. This was that:
- an evaluation of the conditions for the operation of Pristina aerodrome be carried out and procedures be put into effect which are compatible with the rules laid down by the International Civil Aviation Organisation (ICAO), and that civil flights serving Pristina be immediately suspended while these measures are put into effect (and that) particular attention should be paid to the following points :
- the reliability of the radio-navigation aids used, both in terms of their power supply and the quality of the information supplied
- approach, go round and departure procedures
- control procedures and terminology
- documentation published and distributed to crews.
The Investigation noted that the responsible military authorities “immediately followed up this safety recommendation” with the airport being closed to civil traffic pending resolution,
Seven other Safety Recommendations were made at the conclusion of the investigation:
- the opening to international civil traffic of an aerodrome which is not under the effective authority of a contracting State be subject, henceforth, to a complete audit by the ICAO.
- the Italian civil aviation authorities, along with those of any other member states of the JAA in the same situation, apply the JAR OPS regulations in the shortest possible time.
- civil aviation authorities exercise reinforced surveillance of companies with a recently acquired air transport certificate or where there is significant change in an operator’s structure or activity.
- the airworthiness authorities make any modifications mandatory which are designed to improve the operation of equipment of last resort, such as the GPWS.
- a complete test of the GPWS system be included in the pre-flight checklist
- where there is a GPWS mode failure, the JAR OPS 1 amendment make the takeoff of a public transport aircraft subject to establishing and following alternate procedures according to the type of operation and environment.
- ICAO take the initiative in the near future to re-examine the standards applicable to emergency locator transmitters so as to ensure that they correspond to the objective of operating correctly after an accident in order that the aircraft’s location be established rapidly (and that) in parallel, the study of supplementary or replacement systems which permit rapid and precise identification of the location of an accident aircraft be considered as a priority.
The Final Report may be seen in full at SKYbrary bookshelf: BEA Accident Report F-FV991112A (English translation)