FOD Incident Response: Engine Ingestion, Tire Damage and Structural Impact

A Finding Is Not an Incident

A FOD finding is debris discovered before it causes damage. A FOD incident is debris that has caused, or is suspected to have caused, damage. The distinction matters because the objectives differ. For a finding, the goal is to remove the debris, document it and prevent recurrence, as covered in FOD finding response and disposition codes. For an incident, the goal is to preserve evidence, determine the damage mechanism, assess the full extent of damage including hidden damage, identify the source, prevent recurrence and establish airworthiness or operational safety before release. Log an incident in the incident reporting system, not the routine findings log.

Engine Ingestion Response

When debris is suspected or confirmed to have entered an engine, the guide lists seven immediate actions:

1. Shut down the engine per the manufacturer’s procedure. Never try to burn through or clear the debris by running the engine, because blade damage can release fragments and cause cascading damage in downstream stages.
2. Secure the aircraft and surrounding area. Stop further movement and set a security perimeter around the intake and exhaust with no unauthorized personnel inside.
3. Do not rotate the engine. No motoring, dry cranking or turning the fan or compressor by hand. Rotation can damage blades, stators and seals and can redistribute debris.
4. Preserve the intake and exhaust areas. Remove nothing and clean nothing. Debris visible in the intake or on the ground ahead of it stays where it is.
5. Photograph comprehensively from multiple angles: the intake, exhaust, ground area ahead of the intake and along the aircraft path, and any visible debris, with scale references where possible.
6. Log the event in the incident reporting system.
7. Notify per procedures: maintenance control, quality, safety, engineering and, if applicable, the engine manufacturer and the customer.

Assessment starts with a borescope inspection of the whole gas path: fan, compressor stages, combustion section, turbine stages and exhaust. Document every blade, vane, seal and surface, looking for nicks, dents, tears, bending, burning, coating loss and foreign material embedded in surfaces or trapped in cooling holes. If the ingested item is recovered, identify it, because whether it is an aircraft part, a tool, a piece of pavement or wildlife determines the direction of the investigation. If it is not recovered, the borescope may reveal fragments that can sometimes be extracted for identification. Follow the engine manufacturer’s service documentation exactly for inspection requirements, damage limits and repairs, and make no airworthiness decision without manufacturer technical data or an approved engineering disposition.

Tire FOD Damage Response

Tire damage from FOD ranges from minor cuts within limits to catastrophic failure at speed. After a suspected tire FOD event:

1. Inspect all tires on the affected gear, not just the one that looks damaged, since debris that hit one tire may have struck another.
2. If an object is embedded, do not remove it until the tire is deflated and the area is secured. It may be sealing the puncture, and pulling it could cause rapid deflation. Its type, size and penetration angle are also evidence.
3. Photograph the embedded object in place with a scale reference and context showing where it sits on the tire.
4. Deflate the tire per the maintenance manual before removal.
5. After removal, inspect and identify the object, measure the puncture and assess repairability against manufacturer criteria.
6. Inspect the wheel. A penetrating object can damage the wheel in ways that are not visible without disassembly.

Then cross-reference the FOD findings logs for wherever the aircraft operated before the event. Was similar debris reported on recent walks? Checking every location the aircraft visited can point to the source and can also reveal a gap in walk coverage, where debris was present but not found.

Structural Impact Response

When debris strikes the airframe, a control surface, a windshield, a sensor or an antenna:

1. Inspect the impact point for deformation, cracking, penetration, delamination in composites or coating damage.
2. Inspect the surrounding area for hidden damage, because impact energy can travel beyond the visible zone, particularly in composite structures.
3. Preserve any recovered impacting object as evidence.
4. If the impact happened in flight, consider that the object may have been airborne, such as a bird, ice from another aircraft or ground debris thrown into the air. Report to air traffic control if it occurred in controlled airspace, since other aircraft may be at risk.
5. Assess airworthiness per the structural repair manual or with engineering support. “It looks fine” is not an assessment; hidden structural damage is a known failure mode in composite and bonded structures.

Chain of Custody and Evidence Preservation

Debris that may have caused damage can become evidence. The guide sets out a five-step chain of custody: photograph in place with scale and context before touching; bag and tag with a unique identifier, date and time, location, finder, event reference and description; log every custody transfer with date, time, from, to and reason; store in a locked, access-controlled location with logged access; and make the final transfer to the investigation lead with signature and date.

Preservation rules are equally firm. Do not clean the item, because oil, paint, soot or residue can point to its origin. Do not reassemble broken pieces, since fracture surfaces record the failure mechanism and fitting them together can damage them. Bag items separately, keep them clean, dry and temperature-stable away from sunlight, moisture and chemicals, and take the first photograph exactly as found.

Investigating Damage Incidents

A damage investigation asks the routine questions of what the item is, where it came from and how recurrence is prevented, and adds three more: what was the damage mechanism, what was the full extent of damage, and why did existing controls not prevent it. The evidence scope widens to the item, the damage, the aircraft or equipment state before and after, maintenance records, FOD walk records, weather, operational context and human factors. Release decisions come within hours to days, and corrective action within days to weeks. Manufacturers, customers, regulators and insurers may be involved. Methods are covered in root cause analysis for FOD.

Reporting Thresholds

Decide in advance which events require external notification and who may make it. Customer notification is contract-dependent and typically applies to events that affect airworthiness, delivery schedule or product integrity. Regulatory reporting varies by jurisdiction and operation type, and aviation authorities typically require reports of engine ingestion events, FOD-related rejected takeoffs and any FOD event affecting flight safety, so confirm your own obligations. Insurer notification follows policy terms for events above a cost threshold or affecting third parties. Internally, a significant FOD-damage event should reach the accountable executive or equivalent within a defined period, typically 24 hours or less.

Prevention Still Comes First

Every incident reveals a control that failed. Reinforce zones with FOD signs, keep FOD cans within reach of every work area, and use the repeat FOD investigation worksheet and corrective action tracker to close out causes. The free FOD Prevention Program Guide contains the full chapter and templates.