How eliminating FOD can save lives and aircraft.

It’s hard to imagine that a rotor-ingested ball cap, towel, piece of rope, or, as in the recent case of an Airbus EC135 P2+ landing at an Illinois airport, a cloth fire extinguisher cover, could result in hundreds of thousands of dollars in damage and months of downtime. But in the wake of such misfortune, there’s good news: the US National Transportation Safety Board (NTSB) investigations show that accidents from foreign object debris (FOD) can often be avoided.

A Hazard on and above Ground

The EC135 P2+ accident offers a great example of a lesson in preventing FOD. Shortly before touchdown, the main rotor wash blew the cover off a fire extinguisher sitting on the nearby mobile fueling station. As the helicopter’s Fenestron ingested the cloth cover, its metal hub cover detached and was also ingested, causing substantial damage. While industry experts have formally requested that Fenestron hub cover securement be redesigned by the manufacturer, the fact remains that FOD created the hazardous situation in the first place.

“The helicopter was down for four or five months for repairs. The whole tail boom had to be replaced, and because of the sudden stoppage, we had to deal with potential transmission damage,” says Tony Bonham, VP of aviation for Air Evac Lifeteam, which operates 175 air ambulances from 160 bases across 18 states. “Plus, we had delays in getting parts.”

An Airbus EC135 P2+ sustained substantial damage to its Fenestron assembly when a cover was blown off of a fire extingusher and ingested into the tail rotor. The entire tail boom had to be replaced. (NTSB Photo)

When conducting hundreds of flights every year, it’s easy for crews to overlook something or momentarily misjudge the power of a rotorcraft’s vortices. In a 2014 accident in California, a high-time commercial pilot put his jacket inside an unzipped backpack and placed a stowed door on top of it. The jacket was “sucked from the back seat of the aircraft and out the window,” catching in the tail rotor, according to the NTSB’s accident investigation report.

In that case, the pilot was seriously injured, and the Hughes 369D he was flying was substantially damaged. The tail boom severed, the left-side landing gear collapsed, multiple window panels broke, and all main rotor blades, aircraft doors, and the belly of the helicopter incurred damage.

Digging deeper into the NTSB’s investigation reports shows that FOD ingestion doesn’t always happen midair or immediately before touchdown. It can occur after landing during engine cooldown, as it did in two notable cases in 2012, one involving an AS350 B2 in Alaska and the other an R22 Beta in Minnesota. Both times, a tarp lifted into the tail rotor just prior to shutdown and substantially damaged the aircraft. In the Minnesota accident, a fire erupted and the pilot suffered burns to his face and head.

Learning from FOD Accidents

For Air Evac Lifeteam and every other vertical lift operator, FOD accidents are a stark reminder that even small unsecured objects can gravely compromise safety.

“It was a very expensive event but, thankfully, no one was hurt and there was no loss of life. We learned from it. When something like this happens, we work with other air ambulance operators and share information, because every accident affects all of us,” says Bonham.

In the case of the EC135 P2+, opportunities to avoid the accident existed at several points. The person last inspecting the fire extinguisher could have secured the cloth cover under the metal band as was common practice for the organization. The crew member at the landing site could have checked that items on the fueling station were fixed in place or securely tethered instead of playfully waving at the helicopter. (For more best practices, see “How to Reduce Risk from FOD,” below.)

“I think the big lesson learned from the [Air Evac Lifeteam] accident is that foreign object debris can be all around us in the helicopter community,” says Mike J. Hodges, NTSB aviation accident investigator. “It’s an all-hands effort to be cognizant of FOD and to address and remove FOD in the operating environment. It involves everyone—the mechanics working on the helicopters, the pilots and other crew members flying in the helicopters, the line personnel servicing the helicopters, the senior leadership team running the operation, and so on.”

When the FOD accident happened in Illinois, Air Evac Lifeteam’s leadership made a small but important change across their entire operating network, ultimately increasing safety and potentially saving enormous repair costs.

“We pretty quickly made the decision to replace all of the cloth covers so we won’t ever have to deal with that happening again,” says Bonham. “Since it was a canvas cover, we could envision other FOD issues. It could potentially dry rot in the sun and weather, allowing a piece to come off, so we replaced them with a hard plastic container that’s mounted to the fueling station.”

Hodges praises that decision. “It was outstanding that, after the accident occurred, Air Evac Lifeteam addressed the safety issue,” he says. “They deserve big kudos for their actions to help improve safety.”

How to Reduce Risk from FOD

Damage from FOD costs the US aviation industry $474 million annually and the global aviation industry $1.26 billion annually, according to the FAA, plus much more in indirect costs related to delays and downtime. Personnel working with aircraft and near landing sites play an important role in the safety of the aircraft and its crew and passengers.

Based on decades of accident investigations, the NTSB offers operators these helpful ideas for eliminating FOD:

  • Educate everyone working in and around your landing site about the importance of keeping the area free of FOD. Make it part of their responsibility to look for loose objects, and give them time to do so. This includes grounds­keepers, construction workers, mechanics, volunteers, law enforcement, National Guard members, first responders, flight crews—anyone working near your rotorcraft and landing sites.
  • Strongly secure everything, especially hats and caps, cell phones, jackets, and other clothing and gear inside the helicopter and at the landing site. Accident investigations have revealed that items such as tarps, for example, can easily break free from tethers.
  • Designate personnel to conduct a thorough walk-around of the landing site prior to the helicopter’s arrival.
  • Pilots: Scan for FOD during your high and low reconnaissance checks before landing. If in doubt, err on the side of caution and land elsewhere.
  • Avoid landing close to construction activities and trash storage.
  • Consider the effects of wind, rotor downwash, and rainwater drainage on FOD migration when selecting a landing site.
  • Report FOD to management so action can be taken to reduce the risk to personnel and aircraft.

For more information, read the NTSB’s FOD safety alerts for working near landing sites and on rotorcraft.




  • Christine Knauer

    For more than 25 years, Christine Knauer has written for major aircraft OEMs, MROs, and avionics manufacturers as well as aviation trade organizations and publications. She specializes in editorial and marketing content that shares the stories of aviation’s people and machines. Christine holds a master’s degree in aviation safety.

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Christine Knauer

Christine Knauer

For more than 25 years, Christine Knauer has written for major aircraft OEMs, MROs, and avionics manufacturers as well as aviation trade organizations and publications. She specializes in editorial and marketing content that shares the stories of aviation’s people and machines. Christine holds a master’s degree in aviation safety.