On July 25, 2000, a DC-10 shed a metal strip from its thrust reverser while taking off from Paris. Four minutes later, an Air France Concorde was lifting off from the same runway when the unimaginable happened.The plane ran into the discarded metal strip, busting a tire, hurling debris at the plane’s fuel tank and engine, which caused a raging fire. Two minutes later the plane crashed into a hotel, killing 113 people. Each year, foreign object debris (FOD) such as this metal strip causes the air transport industry (ATI) billions of dollars in losses. Here’s an analysis of advances making inroads on FOD detection.
Airlines and airports have investigated numerous ways to reduce FOD-related losses, from initiating personnel awareness and training programs to implementing expensive redesign of aircraft engines and airframes. With up to 70,000 annual incidents, FOD costs each airport as much as US$20 million a year, which adds up to an estimated US$12 billion annually in direct and indirect costs.
Direct costs include such activities as repairing damage to the aircraft, replacing mechanical parts, and paying for human injury. The most frequent FOD-related maintenance repairs are to an aircraft’s engines, tires, skin, hull, and airframe.
Indirect expenses include loss of money from FOD-related flight delays and added fuel expenditures. Delays happen when runways are temporarily forced to close, when unexpected maintenance repairs must be made, or when an aircraft damaged by FOD must be exchanged with one that is flight-worthy. Fuel inefficiencies related to blended engine blades and employee overtime are other examples of indirect costs. In fact, indirect costs are said to be ten times as much as direct costs.
Avoiding Foreign Object Damage
Besides expensive aircraft redesigns, there are many approaches in preventing FOD damage. Airports train personnel on the importance of identifying and properly eliminating debris, while industry and federal groups institute policies and inspections to prevent FOD. Organizations may also utilize innovative technologies to find and remove debris from runways.
Traditional FOD detection programs consist of maintenance crews periodically walking or driving down the runway to manually find and remove debris. However, this antiquated method is not fool-proof, especially when studies show that 70-80 percent of all aviation accidents are from human error. Additionally, having personnel walk the runway takes a great deal of time and can stall operations. And in busy airports such as Charles de Gaulle Airport where Air France’s fatal flight left only four minutes after the DC-10 shed its metal strip, traditional methods fail miserably.
When seconds count, air transport organizations must implement a more reliable means to find and remove runway debris before it becomes a problem. One alternative that is gaining popularity is the use of surveillance and detection technologies to monitor runways.
Benefits of Surveillance, FOD Detection Systems
Disastrous accidents stemming from foreign object debris can be thwarted with the right technology. There are in fact a few FOD prevention systems on the market today.
These detection systems use sensors, cameras, radar, and similar technologies to find pieces of discarded metal, nuts and bolts, garbage, rocks, broken pieces of concrete, birds, and other objects that could potentially cause runway accidents.
The biggest single benefit in using surveillance and FOD detection systems is the ability to spot FOD the moment it is deposited on the runway — before it becomes a problem. This is extremely valuable when aircraft takeoffs are only minutes apart.
Other benefits include the reliability that comes with a computerized system. It reduces the possibility of human error and offers the ability to continuously monitor the runway 24/7, without having to delay airport operations to perform routine FOD runway checks.