There are more than 900 cockpit and/or cabin smoke or fume events a year in the USA, according to the Federal Aviation Administration, many leading to aircraft diversion or return to base because of pilot uncertainty about the origin of the smoke.

California-based IWS Predictive Technologies says that the most common single cause is bearing failure in cooling or air recirculation fans, and although there is a simple fix for this, airlines are proving reluctant to adopt it.

When IWS looked into the reason for airline scepticism, the company found that airline engineering and operations departments do not know the cost of a diversion, turnback or flight cancellation, so the company has commissioned independent aviation analyst Dr Triant Flouris to carry out a broad analysis of schedule disruption costs for a wide range of types of operation. IWS executive John Cox says that Flouris has been given no special terms of reference except to uncover the direct and indirect costs associated with schedule disruption. Cox says he has been quoted a range of airline guesses for diversion cost, starting as low as $600, but no-one actually seems to have troubled to find out an accurate figure.

Because the origin of smoke and fume events in flight is frequently not usually obvious, pilots almost inevitably divert the aircraft to the nearest airport unless it is close to its destination. The IWS solution is a compact, FAA-approved bolt-on unit that detects the onset of bearing failure, shuts down the fan before it overheats producing smoke or fumes, and advises the crew. One airline has told IWS that the fix reduced fan-induced smoke events from one in 12,000 flights to one in a million.

Source: Flight International