Agravel kit is a modification on an aircraft to avoidforeign object debris (FOD) damage or ingestion while operating on unpaved surfaces. Modifications generally include methods of preventing the nose gear spraying FOD into the engine and onto the underside of the fuselage or wings, and methods of preventing each engine from ingesting FOD from the ground directly in front of it.
Examples of planes that can be fitted with this upgrade include theBoeing 737-200, which includes a gravel deflector (similar in appearance to a wide ski) mounted to the nose wheel, and vortex dissipators, using compressor bleed air, in front of each engine.[1] This modification was used byAlaska Airlines for many years, and is still employed byAir Inuit,Canadian North,Air North,Nolinor Aviation in northern Canada. SomeBoeing 727s were also fitted with specific gravel kits on the nose wheel, while the rest were fitted with devices in the form of smaller deflectors than those used on the 737, used on all wheels, to deflect FOD away so as to prevent the rear-mounted engines from ingesting FOD from a runway. Another rear-engined aircraft—theMcDonnell Douglas DC-9/MD-80/MD-90 andBoeing 717 series—uses deflectors similar to those of the conventionally-equipped 727 on all their aircraft's landing gear to prevent FOD structural damage and ingestion. A gravel kit can be fitted toBritish Aerospace 146/ Avro RJ85 aircraft.[2]
| External images | |
|---|---|
 A Canadian North Boeing 737 fitted with a gravelkit | |
| A First Air Boeing 737 fitted with a gravelkit | |
| An Alaska Air Boeing 737 fitted with a gravelkit |
Media related toGravelkits at Wikimedia Commons