Synopsis

On 11 June 2006, a Dornier 328 operated by City Star Airlines whilst positioning in marginal visibility for a day approach at Sumburgh, Shetland Isles UK, and having incorrectly responded to TAWS Class A warnings/alerts by not gaining safe altitude, came to close proximity with terrain . The approach was continued and a safe landing was made at the airport.

Causal and Contributory Factors

The crew were alerted to the situation by on-board equipment, but the commander did not respond to the ‘PULL UP’ warnings it generated. The investigation identified a number of organisational, training and human factors issues which contributed to the crew’s incorrect response to the situation. Two recommendations were made, concerning crew training and regulatory oversight of the aircraft operator.

The following causal and contributory factors are identified from in the official UK AAIB Report on the Serious Incident:

"In this serious incident mandatory equipment designed to prevent such an occurrence functioned correctly and may have averted an accident, though the crew’s reaction to the alert it generated was not in accordance with established procedures. The investigation identified a number of contributing factors:

• The Approach Plan - the initial approach plan that was cleared by the controller was changed in an attempt to cope with the worsening visibility conditions;
• Human Factors - the aircraft’s radar track suggests that the commander, and probably the co-pilot, did not appreciate their position relative to the high ground of Fitful Head, thinking instead that the aircraft would fly to the east of the high ground on its way to a right base position;
• EGPWS reaction - The commander was aware of the high ground at Fitful Head, and when the ‘CAUTION TERRAIN’ alert sounded he probably thought it was triggered by ground he was turning away from, since otherwise his continued descent and gentle turn would be inexplicable;
• Crew Resource Management (CRM) - The commander had an extensive flying background and had accrued a large number of flying hours. In contrast, the co-pilot had joined the company less than a year earlier for what was his first commercial flying position. There was thus a very ‘steep gradient’ across the flight deck in terms of experience and authority;
• Organisational factors - Had the operator met the requirements of JAR-OPS 1 and its own OM in regard of the provision of briefing material for Sumburgh Airport, the crew would have been reminded of the significant terrain and would probably have been reminded about the local weather effects that could affect Fitful Head;
• Crew Training - The GPWS training received by both pilots during type rating training did not extend to practical handling exercises, nor was there a requirement for this under existing regulations. The crew received no training in the predictive functions of EGPWS, and there was no company information or guidance on such alerts."

Recommendations

The following recommendations were made as a result of the investigation:

• "The Joint Aviation Authorities should review the training requirements for flights crews operating aircraft required to be equipped with a predictive terrain hazard warning function, with a view to ensuring that such crews are adequately trained in its use, interpretation and response.
• The Icelandic Civil Aviation Administration should conduct a safety audit of Landsflug ehf (City Star Airlines) in the light of the shortcomings identified during the investigation into this serious incident."

Related Articles

• Controlled Flight Into Terrain (CFIT)
• Situational Awareness
• Crew Resource Management
• Ground Proximity Warning System (GPWS)
• Threat and Error Management Preventing CFIT (OGHFA SE)

Further Reading

• AAIB Bulletin 03/2007 (pp 18 - 32)