Aerospace - Defense

Geoff is concerned that the sole evidence available to investigators, in many large jet aircraft accidents, is the 85 year old paper based weight & balance system, known as the load data sheet.

“This (Lack of alternative evidence) gives rise to what I call the Ice Berg Effect.” Said the retired airline captain.

Smaller aircraft that crash after take off can generally be easily reconstructed and their weight & balance determined independently from the load sheet data.

This was the case in small RPT aircraft Cessna Caravan 208B that killed ten people, nine Canadians and one American, late Saturday, January 17, last year when the small plane crashed into Lake Erie after having taken off from Pelee Island, Ontario, Canada.

This crash that is still under investigation by TSB Canada has caused the release of the following interim information:

The maximum take-off weight in the Cessna aircraft manual is 8750 pounds (cargo pod installed) or 8550 pounds if flying into known icing conditions. The investigation determined that the actual weight of the occurrence aircraft on departure from Pelee Island was approximately 9820 pounds, 1270 pounds over gross weight.
However large aircraft due to;
- higher impact speed;
- larger fuel load;
- more destructive post crash fire are;
-often lost over deep water or,
- inaccessible mountainous terrain,

are more difficult to reconstruct post crash. Often there is little or no aircraft structure, baggage, cargo, fuel or human tissue left to be weighed and relocated on the recovered aircraft.

His concern is shared by many in the accident investigation business, including Acting Chairman Mark Rosenker US National Transportation Safety Board (NTSB).

“The conventional industry logic considers the simplistic ratio of loading error to aircraft weight rather than a more in depth analysis of the many systemic and analytical risks to safety from loading errors.” Stated Captain Ogilvie. I have developed a useful tool called the WBS Threat & Error Model that can be used to determine true aircraft risk of accident from loading error.

The simplistic ratio logic used by many in the industry states that:
A comparison of various aircraft types indicates that the ratio of passenger weight to overall aircraft weight is inversely proportional to the size of the aircraft. For example, in a Boeing 747, the passenger weight represents approximately 9 per cent of the aircraft's weight (450 passengers at 188 pounds, aircraft of 875 000 pounds) whereas the passenger weight in a Caravan can represent approximately 22 per cent (10 passengers at 188 pounds, aircraft of 8550 pounds).

“Nobody knows for sure the true weight or balance of commercial aircraft. They are never weighed or balanced by external means except during a hangar check every few years, and then the aircraft is weighed empty.” Continued Geoff.

The aviation industry has relied on an 85 year old paper based system of computation to determine aircraft weight & balance prior to take off. The system is colloquially known as the load sheet.

A recent fatal accident involving MK Airlines B747 Cargo aircraft that crashed after take off on Runway 34 at Halifax International, Nova Scotia, Canada on October 14, 2004 is a case in point. The accident, which is still under investigation by TSB Canada is being closely followed by many in the industry to determine what part, loading error played in causing this crash.

If, as is suspected by many, the load sheet is the only evidence available to accident investigators then another case can be filed under the surface of the Ice Berg Effect. A valuable chance to gain more accurate weight & balance data on large RPT aircraft accidents will be lost to researchers like Captain Ogilvie.

“If there had been an External Weight & Balance System (EWBS) like Avibridge ™ in use at Halifax then the true threat to aircraft safety due loading error could have been measured, said Avibridge inventor Geoff Ogilvie.

“When are regulators going to face up to their responsibilities and fund research and development to produce a system that is independent, accurate, and verifiable and provides a final check and warning to the pilot of overweight or out of balance condition prior to take off.” Concluded Geoff Ogilvie.

Press Release authorised by Geoffrey K Ogilvie, CEO Avibridge.com
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Avibridge.com is an organisation seeking development funding for an Avibridge ™ model and Avibridge ™ prototype.

© Copyright Geoffrey K Ogilvie 2005