Story ID: 
AINsight: FOD for Thought
By: Stuart “Kipp” Lau
Caption: Foreign objects can lead to serious aircraft incidents and accidents
Word Count: 1544
Foreign object debris (FOD) is a contributor to aircraft damage, serious incidents, and accidents in aviation. The problem is large and continues to grow. FAA reports suggest that FOD costs the U.S. aviation industry nearly $500 million annually; it is not only costly but can be deadly.
It is easy to see how the costs add up. Last year, a single misplaced flashlight caused $4 million in damage to the engine of a U.S. Air Force Lockheed F-35A. Following this mishap, an Air Force Times article stated that FOD was one factor that caused the number of ground accidents to nearly double from 2022 to 2023.
Beyond the physical damage to an aircraft, FOD damage can be catastrophic. In July 2000, an Air France Concorde departing the Charles de Gaulle Airport struck a piece of metal, blew out a tire, and the debris caused the aircraft’s fuel tank to rupture. Leaking fuel ignited, and two of the four engines flamed out. The aircraft crashed, killing nine crewmembers, 100 passengers, and four people on the ground.
The FAA defines FOD as “any object, live or not, located in an inappropriate location in the airport environment that can injure airport or air carrier personnel and damage aircraft.”
Most FOD awareness campaigns focus on tool control programs for mechanics and keeping ramp areas and hangar floors clear of debris for aviation workers; rarely are pilots reminded to keep track of their own personal equipment or other objects on the flight deck.
Tools, hardware, rags, and other objects left behind and unaccounted for by maintenance personnel can become FOD. The FAA says maintenance personnel must account for all items when performing maintenance tasks. FOD can be ingested into the engine or interfere with critical flight control systems, potentially leading to a serious incident or accident.
Likewise, pilots contribute to FOD events by dropping items such as water bottles, pens, pencils, clipboards, and electronic devices on the flight deck. If not recovered, these objects can become lodged in flight controls, potentially causing loss of control.
According to NTSB Safety Alert “Control Foreign Object Debris,” the Board has investigated several accidents involving FOD left behind by maintenance personnel. But FOD on the flight deck can be just as serious.
Shop Rags Take Out a Huey and MD 500E
The pilot of a UH-1B Huey helicopter reported that “she heard a loud noise, followed by a bang, and the low rotor RPM horn.” Shortly after, the pilot entered an autorotation, touched down on a hillside, and the helicopter rolled over. According to the report, earlier on the day of the accident, the engine had been replaced. Investigators found material that was consistent with a towel in the inlet guide vanes and the compressor section of the engine.
In another event, the pilot of an MD 500E was conducting a post-maintenance check flight when the engine lost power and the pilot began an autorotation maneuver. The helicopter landed hard and rolled on its right side. Investigators examining the engine found cloth rags ingested into the engine air intake.
Other FOD-related cases destroyed two separate general aviation aircraft. In the first case, a Kitfox Series 5 aircraft lost control and crashed into the Atlantic Ocean. Once recovered, investigators found a common hardware clamp and leather work glove impinged in the elevator control system, leading to the loss of control.
In the other case, paint chips obstructed the fuel filter of a Grumman AA-5B Tiger. The Grumman, complete with a new paint job, lost power during cruise flight due to fuel starvation and crashed during an attempted forced landing.
Water Bottle Damages Avanti
In a recent NASA ASRS report, pilots nearly lost control of a Piaggio P.180 Avanti during landing. The culprit: a water bottle. Fortunately, during this event there were no injuries and damage to the aircraft was minimal.
According to the pilot in command (PIC), who was the pilot flying, “Upon landing my water bottle fell and lodged between the left rudder and the side wall of the aircraft.” Then the PIC handed off control of the aircraft to the second in command (SIC). The PIC then told investigators, “I put my head down to recover the bottle and when I raised my head the aircraft had braked to a stop. Both main tires had blown.”
The SIC recounted, “Upon touchdown, the flying pilot’s water bottle fell down by the rudder pedals. After a bit of swerving and control issues, the flying pilot said, “your rudders” and passed the airplane off to me. At this time, we were pulling to the right headed to the grass off the side of the runway. I used rudders and braking force to get us stopped and able to stay on the runway. The brakes locked up and the tires blew.”
iPad Kills Two in Chinook Accident
A July 2022 crash of a CH-47D Chinook helicopter engaged in fighting a wildfire was much more serious, killing the two pilots. Contributing to the accident, according to the NTSB, was an iPad found in the river near the crash site. “Specific damage to the iPad is likely tied to the cause of the crash,” said NTSB investigator Clint Johnson.
Johnson said, “What the investigative team found, at the end of the day, was most likely that the iPad that was in the cockpit, fell in between the controls, the control pedals, the yaw control pedals, and ultimately played a part in the accident.”
Three distinct gouges on the iPad recovered from the accident site led investigators to match those witness marks to flight controls in the cockpit of the helicopter. The NTSB released these details before release of the final accident report to “get the word out” and to prevent a similar occurrence.
Preventing FOD Incidents and Accidents
The NTSB Safety Alert on FOD recommends the following for maintenance personnel:
• Perform an inventory of tools, personal items, and personal protective equipment before working on an aircraft. Take only what is necessary for the specific maintenance task. Place nonessential personal items (such as jewelry, coins, keys, etc.) in a secure location.
• Cover up engines, pitot static ports, air inlets, and other areas with protective materials to reduce the likelihood of FOD migration to critical flight systems.
• Ensure the proper lighting is used to check for FOD left behind during maintenance.
• Keep hardware and consumables in appropriate containers to prevent them from becoming FOD. Store tools and organize them in a manner that you can easily recognize if one or more are missing. (Good tool control practices incorporate toolboxes with cutouts for each tool.)
• Avoid or manage distractions. Always follow the manual/task card and use a checklist. If you get distracted, go back (at least) three steps when restarting your work.
• Clean as you go to reduce the likelihood of leaving any items. Keep a FOD container near your workstation to dispose of FOD.
• After you have completed a task, perform a second inventory of tools, personal items, and personal protective equipment. Remove all aircraft protective material and dispose of it in an appropriate container.
• Have another mechanic visually inspect your work and work area. A second set of eyes may see something that you missed.
• Recognize that human factors issues such as complacency, fatigue, time pressure, stress, and a lack of situational awareness can contribute to FOD.
• Consider conducting daily FOD walks to identify and remove FOD from ramps and hangar floors.
While the NTSB Safety Alert does not address flight crew, these actions can help pilots prevent a FOD encounter:
• If you drop something, pick it up immediately.
• During the exterior preflight inspection, ensure that all inlets or open access areas are free of FOD. Also, ensure that all doors and access panels are securely closed.
• During the interior preflight inspection, ensure that all personal equipment and other items are secure and will not move during takeoff or landing.
• Use a flashlight to look behind the rudder pedals to inspect for loose objects such as water bottles, pens, pencils, tools, and other items.
• Do not store items in areas that will restrict movement of throttles or thrust levers, or primary or secondary flight controls.
• Before every takeoff, perform a flight control check to ensure the free, full, and correct movement of each flight control surface.
• If you use an EFB, make sure that it is securely mounted and won’t move during flight.
• Inflight, prior to landing, remove catering supplies from the cockpit and secure all liquid containers, such as water bottles, soda cans, and coffee cups.
• Never pass liquids over avionics or other electrical equipment—spillage can disable critical components such as audio control panels, radios, etc.
The opinions expressed in this column are those of the author and not necessarily endorsed by AIN Media Group.