C3/2002L Violation of the Radar Separation Minima in the Vicinity of Helsinki Terminal Area on 17 January 2002

An air traffic incident occurred within Helsinki Terminal Control Area (TMA) on Thursday 17 January 2002 at 14.18 UTC, when a Fokker F28 Mk 0070 aeroplane, call sign MAH742, which was operated by the Hungarian Malev Airlines on a scheduled passenger flight from Budapest to Helsinki, and a Fokker F27-400M aeroplane, call sign C21, operated by the Finnish Air Force on a flight from Jyväskylä to Helsinki, passed each other with a distance of about 1.85 nautical miles (NM) violating the radar separation minima required by the authority. The separation minima was violated because MAH742 did not initiate an anticipation turn before waypoint HK707 in accordance with the area navigation (RNAV) procedure, while flying the Porvoo 1C RNAV transition route for Helsinki-Vantaa airport as specified in its arrival clearance. MAH742 had 22 passengers and five crew members on board. C21 had 21 passengers and a crew of three. The Accident Investigation Board, Finland, initiated an official investigation of the incident on 29 January 2002. Vesa Palm was appointed as investigator-in-charge, and Ari Huhtala as a member of the investigation commission. Airline transport pilots Lauri Laine and Pauli Perttula were also invited as experts on flight operations. The Hungarian accident investigation authority did not appoint an accredited representative for the investigation.

MAH742 had been cleared for RNAV transition to runway 15 and to descend to 2000 feet. C21 was being radar vectored on heading 230º and reported maintaining the altitude of 4000 feet. The Traffic Alert and Collision Avoidance System (TCAS) of MAH742 indicated C21 flying on an intersecting track almost at the same altitude. When the air traffic controller noticed that MAH742 did not initiate a turn before waypoint HK707 as required by the Porvoo 1C transition procedure, he told MAH742 to turn left to heading 220º and C21 to turn right to heading 330º. The required radar separation minima of three nautical miles was lost in this situation.
The material available for investigation revealed no malfunctions in the systems of MAH742. On the other hand, the RNAV transition procedures for Helsinki-Vantaa were designed by the Finnish Civil Aviation Administration (FCAA) to be based on Precision Area Navigation (P-RNAV), but the methods used in their implementation and publication were not in accordance with EUROCONTROL rules effective at the time of the incident. MAH742 and several other aircraft were flying the P-RNAV procedures of Helsinki-Vantaa with equipment and approvals valid only for Basic Area Navigation (B-RNAV). The investigation revealed also minor deficiencies both in cockpit crew and air traffic controllers operations.

The reason for the infringement of radar separation minima was that MAH742 did not follow the Helsinki-Vantaa PVO 1C transition route as given in its arrival clearance. The aircraft did not initiate an anticipation turn before waypoint HK707. The exact cause of the incident could not be determined with certainty in the investigation. A technical malfunction or crew error could not be fully excluded. A contributing factor was that the pilot-in-command did not abort the lateral navigation conducted by the Flight Management System (FMS) and change into HEADING mode of the autopilot, or change into manual control and request radar vectoring, although he saw in the cockpit the transition route on the navigation display as rectangular, without anticipation turn routing. Moreover, the level of and device requirements for the RNAV procedure were not clearly indicated on Helsinki-Vantaa transition charts, which may also have affected the sequence of events. If the procedure had been easily identifiable, as required by EUROCONTROL instructions, the crew of MAH742 could have noticed that they were not appropriately certified to comply with the RNAV transition clearance given. In addition, the air traffic control did not monitor that the planned vertical separation was achieved between MAH742 and the Air Force C21 either. If the vertical separation had been achieved as planned, the incident would probably have been avoided.

As a result of the investigation, the investigators recommends that the current organizations of the FCAA Air Navigation Services Department and Flight Safety Authority, as well as the quality assurance systems of both the FCAA public utility company and Flight Safety Authority, should develop the mechanisms for safeguarding their operations so that e.g. any deficiencies in the design and implementation of navigation procedures could be detected more certainly and corrected in time. Furthermore, the Air Navigation Services Department shall ensure that air traffic services units always have adequate flight plan data at their disposal. The Hungarian CAA shall require Malev Airlines to revise the Flight Operations Manual, Part A (FOM-A) to contain procedures for the handling of FDR and CVR recordings as specified in the JAA requirement

JAR-OPS 1. In addition, Malev Airlines shall require their cockpit crews to report as precisely as possible any faults and malfunctions detected especially in aircraft FMS in RNAV operations, as well as to inform flight safety authority and manufacturers of equipment of their observations.

According to EUROCONTROL guidance material (ESARR 2 Guidance to ATM Safety Regulators, EAM 2/GUI 1, Severity Classification Scheme for Safety Occurrences in ATM, Edition 1.0, edition date 12-11-1999) this incident is classified as A3.

C3/2002L Report (pdf, 0.64 Mt)

Published 17.1.2002