Between 1 January 1998 and 31 December 2008 there were 398 ground occurrences involving high-capacity aircraft reported to the ATSB.
Of these, around 70 per cent related to ground operations and the rest involved foreign object debris (FOD).
According to a new ATSB report, the most commonly reported phase or location of ground operations occurrences was on a taxiway, accounting for about 34 per cent of occurrences. This was followed by gate occurrences at about 28 per cent, pushback at about 26 per cent, and approaching the gate at about 11 per cent. Similar types of occurrences were seen between different locations/phases.
Six different types of occurrences accounted for about 75 per cent of all ground operations occurrences, with failure to comply with a clearance being the most frequently reported occurrence type. The other category (about 25 per cent) included a mixture of collision or near collision occurrences with aircraft by aircraft, aircraft collisions with objects, buildings or vehicles, refuelling occurrences, flight crew perceptions, jet blast, weather-related and injury, animal strikes, and engine start up and shutdown.
There were 116 FOD occurrences reported to the ATSB between 1998 and 2008 that affected high capacity air transport aircraft. The number of FOD occurrences has increased in a curvilinear fashion from seven in 1998 to 26 in 2008.
Foreign object debris comes from many sources. Material sometimes falls from aircraft, maintenance vehicles, and aircraft handling equipment onto runways, taxiways, and the airport aprons.
In the case of aircraft, the physical stresses exerted during takeoff and landing place high loads and vibrations on tyres, engines (reverse thrust), and landing gear components, which can cause poorly secured components to loosen and separate.
Weather also influences the prevalence of FOD, with winds blowing debris on to runways, but occasionally aircraft contaminate a runway or taxiway with rocks and dirt as a result of jet blast.
The most common FOD reported to the ATSB was aircraft components, and these made up about 25 per cent of all reported FOD occurrences. In terms of high capacity aircraft, components making up the engine reverse thrust assemblies were most commonly reported and included blocker doors, door assembly pins and bolts, bushes, and plates.
Less commonly reported FOD items from aircraft were landing gear doors, delaminated material from flaps and control surfaces, struts, and landing lights. Most of these components were found on the runway strip rather than on or near taxiways and airport aprons.
Tools or pieces of equipment were the second most common FOD event reported to the ATSB, accounting for about 19 per cent of all FOD occurrences.
The reports showed a variety of tools and equipment were found on runway strips, taxiways, and aprons, including screwdrivers, a 15 litre can of paint, spanners and wrenches, a torch, wire, a headset, and rags. Less commonly found were vehicle horns, rotating beacons, and cone markers.
In about another 16 per cent of FOD occurrences, the object was not identified, and in about 12 per cent of FOD occurrences, the object found was metal, but it was not possible to tell if the component was from an aircraft or another source. These metal objects included bolts, brackets, metal plates, and poles.
About 11 per cent of FOD occurrences reported to the ATSB led to airframe, wheel, or engine damage. Four FOD occurrences occurred during takeoff, with one resulting in engine ingestion and a subsequent return to the aerodrome, and three resulting in a tyre blowout and rejected takeoff or return to the aerodrome.
FOD occurrences had no effect on the aircraft operation in about 80 per cent of occurrences, but where it did, the most common consequential events were go-arounds and rejected take-offs.
To view the full report go to http://www.atsb.gov.au
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