FOD (foreign object debris) is the scourge of airport operations. FOD includes the mundane as well as the unusual: baggage-claim tickets, random bits of plastic, airplane parts, dead animals, rocks, and clumps of loose dead vegetation. Keeping runways and taxiways clear of FOD is a seemingly never-ending battle; airports’ operations areas are festooned with signs both warning of the dangers of FOD and reminding airport personnel to constantly be watching for, and picking up, such trash.
According to a 2013 FAA fact sheet, “FOD can be ingested in an aircraft engine, which can result in damage to the aircraft or cause an accident. It can damage or become lodged in aircraft operating mechanisms or cut aircraft tires. Boeing estimates that FOD causes an estimated $4 billion in damage to engines and aircraft taken out of service each year.”
Wikipedia’s entry on FOD claims the total is significantly higher, citing a now-offline 2008 report claiming $13 billion in direct and indirect costs to the aviation industry as a whole. In either instance, FOD damage is very expensive, and it makes sense that every airport have a FOD management plan.
Aircraft are designed with an eye toward reducing the potential for FOD damage while traveling along runways, aprons, and taxiways. Features such as tall landing gear that raise the height of engine intakes, the mounting of engines high on the rear of a fuselage (such as Boeing’s 727, the venerable MD-80, and the Bombardier CRJ), or even atop the wings (as with the HondaJet), while not always originally designed specifically for FOD avoidance, definitely take it into consideration.
Many helicopters have elaborate engine-air intake systems designed to keep ingested foreign objects away from delicate engine internals. In extreme cases, FOD has brought down aircraft to tragic effect (see Air France’s Concorde flight 4590).
Seattle-Tacoma International Airport recently organized its 23rd annual FOD walk, in which roughly 100 properly-badged airport and airline employees, service providers, and subcontractors walked side-by-side along the grassy areas between the runways and taxiways. The exercise takes several hours, and results in a surprising collection of junk.
The walk offers an opportunity like no other to experience aircraft movements as closely as anyone is ever likely to; it’s definitely excellent compensation for picking up someone else’s trash.
Certain bird species are classified as being particularly hazardous to aircraft based on either hunting, flying, or preferred nesting habitats. Sea-Tac Airport Media Officer Brian DeRoy provided us with a list of the bird remains from species classified as hazardous that were found during this year’s walk:
- Osprey: 1
- Red tailed hawk: 2
- Gull: 2
- Barn owl: 5
- Dove/pigeon: 1
- American kestrel: 2
This year’s total FOD collection resulted in two truckloads of debris, including lots of paper and plastic luggage tags, candy wrappers and food containers, one aircraft tire piece, one small aircraft access door that DeRoy compared to an automobile gas cap in size, and a variety of aircraft body pieces. There was no total weight available this year.