B733, vicinity Helsinki Finland, 2008

B733, vicinity Helsinki Finland, 2008

Summary

On 26 March 2008, a Ukraine International Airlines Boeing 737-300 being vectored by ATC to the ILS at destination Helsinki in IMC descended below its cleared altitude and came close to a telecommunications mast. ATC noticed the deviation and instructed a climb. The investigation attributed the non-compliance with the accepted descent clearance to the failure of the flight crew to operate in accordance with SOPs. It was also noted that the way in which ATC safety systems were installed and configured at the time of the occurrence had precluded earlier ATC awareness of the hazard caused by the altitude deviation.

Description

On 26 March 2008, a Ukraine International Airlines’ Boeing 737-300 operating a scheduled passenger flight from Kiev to Helsinki descended below its ATC cleared altitude and MSA in day IMC whilst being vectored to the ILS and camer close to a telecommunications mast before ATC noticed the error and ordered it to immediately return to the cleared altiude. There were no abupt manoeuvres and none of the 29 occupants were injured.

Investigation

An Investigation was carried out by the Accident Investigation Board Finland (AIBF). FDR and CVR data was not available but QAR data was and this proved invaluable to the Investigation. This data showed that the aircraft had descended to an altitude of 1400-1500 feet in the vicinity of the 1227 feet high mast before ATC instructed a climb. It was noted that the First Officer had been PF.

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