\nBurst Tires Lead To Loss Of Aircraft Control<\/h3>\n
Early in my career, I was on a detachment at RAF Waddington, near Lincoln, England, when an F4 Phantom blew a tire on landing. The aircraft immediately departed the runway, ran onto the grass in the center of the airfield, and sped toward cabins where the ground crew and I were operating.<\/p>\n
The pilot fought with the controls but as the aircraft sank into the muddy field, he was unable to adequately retard the speed or, more importantly, steer the nose wheels to control the direction. At less than five hundred yards from the buildings, the pilot was faced with a split-second decision, and he and his navigator ejected.<\/p>\n
The aircraft carried on its path, held firmly in its mud tracks, but as it continued to sink up to its axles and the landing gear doors, its speed rapidly declined and it came to rest a few hundred yards short of the buildings. Several seconds later the pilot and navigator, both now under parachute, landed safely on the airfield.<\/p>\n
Although no one was hurt, it is an event that I will never forget and one that has served as a reminder of the hazards of aircraft operations and of FOD.<\/p>\n<\/blockquote>\n
FOD Is A Threat To Turbine Engines<\/h3>\n
For the uninitiated, turbine engines can rotate at over ten thousand-rpm, and when a tiny piece of debris like a piece of safety locking wire or stone get ingested it behaves in a ballistic manner, striking the compressor blades as if fired from a gun. Depending on material grade, shape and size, the debris can cause damage to the first blade or any part of the intake they strike. <\/p>\n
As the debris passes through the engine, its many contacts by fan blades can break it into smaller chunks or the debris can liberate pieces from the blades that multiply the debris field and increase the size and quantity of the damage.<\/p>\n
![\"\"](\"https:\/\/www.fodcontrol.com\/wp-content\/uploads\/Content\/Stock\/EngineXray2-e1668792748277.jpg\")
I have seen a small nick on the first stage of the fan and seen the rear stages of the compressor and most of the turbine rotors completely decimated, as if someone had taken barber shears and clipped the blades from the disk. Where the blades are highly loaded or are subject to vibration \u2014 sometimes referred to as HCF (High Cycle Fatigue)<\/a> \u2014 the damage to the blades can grow rapidly to a crack and subsequently fail.<\/p>\nCatastrophic Engine Damage <\/h3>\n
Although engines are designed to contain failed blades, a blade failure can lead to the total destruction of the engine. Indeed, many posters exist that show how the ingestion of a small metal screw, which costs just a few pennies, can cause damage requiring the complete replacement of the engine, which costs many millions of dollars.<\/p>\n
However, it is not just hard debris that causes damage; a plastic bag can behave like a large sheet and blank the intake, stalling the airflow across the blades and causing the engine to surge. Engines can usually tolerate a surge \u2014 a reversal of the airflow \u2014 but, depending on severity, a surge can deform blades and necessitate the replacement of the engine.<\/p>\n
Foreign Object Elimination Is Our Mission<\/h3>\n
It is easy to see why we must control debris to maintain safety and reduce costs. FOD is correctly seen as a flight safety risk, and everyone is responsible for keeping that risk as low as possible.<\/p>\n
\nPicking up debris that could migrate onto airfields is the first step that could avert a disaster.<\/p>\n<\/blockquote>\n
True, seldom does FOD result in a disaster, but it can be one link in a chain of events that, if left unbroken, could result in the failure of an engine, loss of aircraft and taking of life. Breaking that chain could be as simple as picking up litter. A key area to achieve maximum benefits is through training and education. More can be done if we target areas for improvement and coordinate increasingly limited resources to reduce problems and get the best return of investment.<\/p>\n
Sources and Mechanisms of FOD<\/h2>\n
Understanding how engines ingest debris is important<\/a>.<\/p>\n\t\n\t\t\n
![\"FOD](\"https:\/\/www.fodcontrol.com\/wp-content\/uploads\/Content\/Stock\/fighter-jet.jpg\")
Work areas are kept scrupulously clean and well maintained, tools are kept in good condition and rigorously controlled, and personnel are specifically trained and regularly refreshed on the hazards of FOD and the need to be vigilant \u2014 even those not associated with aircraft operations.<\/p>\n![\"Air](\"https:\/\/www.fodcontrol.com\/wp-content\/uploads\/Content\/Stock\/concorde.jpg\")
A massive fuel leak ensued, to be ignited by an electrical arc from wiring in the undercarriage that had been damaged by the tire failure. Further damage was caused to hydraulic pipes and controls, stopping the undercarriage from being retracted and causing a loss of power on the number one engine and the second to cut out. At this stage it was too late to abort the take off.<\/p>\n