By David Learmount in Cranfield
Cranfield University is launching a take-off performance monitor (TOPM) that is being prepared for industrial production, according to its co-inventor Dr Martin Eshelby.
Last month the Canadian Transportation Safety Board (TSB) took the unusual step of recommending, in its final report on the MK Airlines fatal Boeing 747-200F accident at Halifax Nova Scotia, that the commercial air transport industry should aim to fit a TOPM, even though there is no certificated system yet available.
The TSB chief investigator William Fowler told Flight International that his team made the recommendation because, although the MK Airlines accident on 14 October 2004 may have been one of the most tragic outcomes of a crew's failure to detect inadequate acceleration during the take-off run, the problem has occurred frequently.
In the recent past, two other 747s - and other types - have only narrowly escaped disaster, most often because of an error in the crew assumption about the aircraft's weight, or an error in entering data into a flight management system before flight. Fowler says these repetitions "demonstrate that this is a systemic problem, and we could not ignore it just because - at present - there isn't a solution".
Software solution |
|---|
|
The Cranfield TOPM is a software solution that can be loaded into an aircraft's flight management system. An indicator bar - displayed only between the start of the take-off roll and decision speed (V1) - is on the left of the air speed indicator (ASI) "tape" in the primary flight display. The system measures acceleration to detect "subtle" differences between the actual rate and the rate the aircraft should be developing. It is designed to be "informative, not executive" - to aid the pilots' decision-making, not to make decisions. Flight International has "flown" the Cranfield TOPM in a Boeing 747 simulator with an external visual system. Next to the ASI tape, the pilot sees one of two basic alternatives: a green vertical bar above the level of the actual ASI "window", its height proportional to the acceleration margin above the minimum acceptable performance; or a red vertical bar extending below the ASI window that shows the converse. Its significance can be absorbed at a glance by the pilot during the take-off run. |
At the time of the MK investigation, Cranfield's Eshelby had already demonstrated his TOPM system to the UK Civil Aviation Authority and the Air Accidents Investigation Branch (AAIB), both of which told him it had potential. Because MK Airlines is a UK-based airline, the AAIB was involved in the TSB's MK investigation, and when it became apparent the accident was caused by a weight data entry error and consequent slow acceleration that the crew did not detect until too late, the AAIB told the TSB about the Cranfield system, and Eshelby took it to Canada to demonstrate it.
Fowler emphasises that it is not his task to recommend a specific system. He says he knows Cranfield is not the only organisation working on developing a TOPM.
Source: Flight International
