Predictive Technologies to Reduce Diversions

Predictive technologies are desired to avoid simply reacting to accidents. Examples include predictive flight path monitoring in Terrain Awareness Warning Systems and predictive windshear monitoring. These applications of predictive technologies warn flight crews of pending dangers in time for them to react and avoid an accident. Technology to predict and actively intervene, by stopping a smoke producing component (e.g. fans) before the smoke begins, has significant potential benefit. By shutting down components such as air cycle machines, fans, or other rotating components, the cases of diversions due to odour and smoke of undetermined origin would be decreased.vmu1

An example of the significance of component caused smoke odours is the Boeing data showing that the number one most common cause of smoke in the B757 are fans in the air conditioning system (Boeing, 2000). Operators using predictive technology on these fans have fewer in-flight smoke events resulting in a lower number of diversions (Rosenkrans, 2011). There is a safety, financial and operational benefits of improved reliability.

Smoke, Fire and Fumes

The smell of smoke or fumes could be the first indication of a fire.  History has taught the aviation industry never to ignore the threat of a fire.

Luckily, most incidents of smoke or fumes are not from a fire, but often are from failing components, electrical failures, or bleed air contamination which can still have an impact on the operation of the aircraft.

slidesblown1Positive visual identification of the source of the smoke or fumes, and visual confirmation that the source is extinguished, is the only means for allowing continued operation of the flight.  Unfortunately, the root cause can not always be accurately verified in-flight by the Flight Crews, and only by Maintenance or Engineers after a thorough investigation of the event.  Without positive identification of the source, the Flight Crews have little choice except to divert the aircraft, and in many instances, declare an emergency.

Current FAA data reflects smoke/fume related incidents occur on an average of 3 per day just in the US alone.

Following Exerpt from:


Royal Aeronautical Society; Specialist Paper – Second Edition 2013

Since the Swiss Air Flight 111 accident, flight crews have shown an increasing willingness to divert at the first indication of a potential smoke/fire/fume event.

Additionally, the FSF industry standard checklist includes the potential need to divert near the top of the checklist. As a result of this approach to a potential event, the number of diversions due to non-fire events has increased. These diversions are expensive for the operators, and if they are caused by false warnings they can desensitize flight crews.

The cause of these non-fire events are numerous, including overheated fans, bleed air odours, galley ovens, and many more. Of the three diversions, which occur daily, (over 900 annually) many are caused by non-fire events. (International Air Transport Association, 2005).