Foreign Object Damage (FOD)
Summary of USAF FOD mishaps by fiscal year
Sweeper
Large sweeper
MTV offset from paver during night construction
Foreign Object Damage (FOD) is the damage caused by any object that if run over, ingested or hit by an aircraft can cause damage to the aircraft. Foreign objects can be any number of items including rivets, nuts, bolts, luggage, keys, wheels, rocks, HMA chunks, nails, wood, plastic, tools, birds, etc. Foreign objects can damage aircraft engines, wings, fuselages and tires and cause millions of dollars in damage each year.
Contractors must understand the seriousness of FOD and its safety implications. Consider the following:
- In fiscal year 2004 the U.S. aerospace industry reported 259 FOD incidents of which 119 were considered preventable, costing almost $48.5 million in damage. Of those 259 incidents, 38 were due to runway debris (the second most after hardware/tools) (Henry, 2005).
- Using internal company data, United Airlines have calculated their FOD-related expenses (parts and labor) each year and come up with a high of $24 million in 1999 and a low of $8 million in 2005 (the latest year for data) (Franklin, 2005).
- U.S. Air Force FOD mishaps have ranged from 42 to 105 per year between 1995 and 2004 costing between $5 and $50 million per year (see Image)
- It costs $3.2 million to replace an F110-GE-400 engine (the engine used to power the Navy’s F-14 Tomcat) and over $330,000 to rebuild it after a FOD incident (Turner, 2006).
- Boeing (AERO, 1998) lists the 1998 cost of a new MD-11 engine at $8-10 million and the cost to repair a FOD damaged MD-11 engine at $0.5-1.6 million. Indirect costs such as flight delays, schedule disruption, injury liability and other additional work can cost much more.
FOD prevention in HMA paving involves the following:
- Training. FOD awareness is typically part of the mandatory training paving crews must receive before they are allowed to work in the AOA.
- An increased awareness of FOD by the paving crew. FOD is not as serious an issue in highway paving. Thus, paving crews used to doing highway work need to exercise increased FOD awareness. End-of-shift FOD walk-downs (where the crew walks the entire site looking for and removing foreign objects) are a best practice. Attention to detail during routine operations is important; items as small as sandwich wrappers can cause significant damage.
- Extra sweepers on HMA paving worksites. One or two sweepers (see Image) operating with any milling machine along with a sweeper used for general site cleanliness (see Image).
- Careful attention to tack tracking. Dump trucks driving on tack coats can track tack along the haul route. Rocks and debris can become stuck in the tack such that sweeping or vacuuming will not remove the rocks. If the rocks later become dislodged, they are a FOD hazard. Two techniques to mitigate tack tracking are:
- Use a material transfer vehicle and offset it from the paver such that trucks unloading into the MTV are driving on untacked surfaces only (see Inage).
- Wet down the haul route with a water truck. Rocks will not stick to wet tack and can thus be swept or vacuumed up.
