A. Non- FOD Sensitive An area where the risk associated with a FO is negligible and no FOD control measures are needed.

B. FOD Awareness Area An area where the risk associated with a FO resulting in hardware damage/contamination is low.

C. FOD Control Area An area where the risk associated with a FO resulting in hardware damage/contamination is medium.

D. FOD Critical Area An area where the risk associated with a FO resulting in hardware damage/contamination is high.

Foreign Object (FO) and Foreign Object Damage (FOD) Definitions APPENDIX

A.1 Clean-As-You-Go - Defined by National Aerospace FOD Prevention, Inc. (NAFPI) as follows: “Clean the immediate area when work cannot continue. Clean the immediate area when debris has the potential to migrate to an out of sight or inaccessible area and give the appearance of poor workmanship. Clean the area prior to leaving it unattended, when work cannot continue, after work is completed or at the end of shift, whichever comes first. If you see something, drop something, see or hear something drop, pick it up.”

A.2 Consumables - For the purposes of this procedure, supplies provided to workers that are considered expendable; i.e., personal protective equipment, sealants, solvents, paint, brushes, applicators, sandpaper, rags, wipes, rivets, washers, fasteners, and other hardware.

A.3 Corrective Action Plan - Steps to be taken to prevent the root cause(s) of a FO and/or FOD incident from occurring again. The corrective action plan is not the direction necessary to remove the FO and restore the hardware.

A.4 Critical Foreign Object - FO debris that has a significant probability of causing system or component malfunction or deterioration if the item containing the FO debris is put into use.

A.5 Foreign Object Damage (FOD) - Any damage attributed to a FO that can be expressed in physical or economic terms, which may or may not degrade the product’s safety and/or performance characteristics.

A.6 Foreign Object (FO) - A substance, debris or article alien to a vehicle or system that would potentially cause damage.

A.7 Foreign Object Damage (FOD) Awareness Area - Any area designated as a low-risk area where quality sensitive products or hardware are in place and exposure to FOs would potentially cause a system or product malfunction or failure. Organizational Culture is focused on safety, reliability, and functionality by protecting all personnel, products and services from FO debris and damage.

A.8 Foreign Object Damage (FOD) Control Area - Any area identified as a medium-risk area where quality sensitive products or hardware are in place and exposure to FOs would potentially cause system or product damage, malfunction or failure. Stringent accountability measures shall be applied to control the risk of FOD in the area.

A.9 Foreign Object Damage (FOD) Critical Area - Any area identified as a high-risk area where quality sensitive products or hardware are in place and exposure to FOs would potentially cause system or product damage, malfunction or failure. Strict accountability measures shall be applied to control the risk of FOD in the area.

A.10 Foreign Object Damage (FOD) Sensitive Area – any area designated as either a FOD Awareness Area, a FOD Control Area, or a FOD Critical Area.

A.11 Foreign Object Damage (FOD) Sensitive Work – Work that is being conducted in a FOD sensitive area.

A.12 Foreign Object (FO) and Foreign Object Damage (FOD) Incident - An instance where a FO or FOD is found.

A.13 Housekeeping - Basic element of controlling a safe and effective work environment. Proper cleaning and organizing techniques are followed to ensure the prevention and elimination of FOs. Maintenance, manufacturing, testing and all other operational areas shall remain clean and organized with the ultimate goal to prevent debris from migrating into critical and complex hardware and facilities. The clean-as-you go work ethic is one of the most effective provisions for production, service, and preservation of products.

A.14 Non-FOD Sensitive - An area where the risk associated with a FO is negligible and no FOD control measures are needed.

A.15 Shadowbox - A tool box with specific, marked locations for each tool so that a missing tool will be readily noticeable.

A.16 Tether - A lanyard of sufficient strength (wire, rope, cable, etc.) attached to the tool/equipment and to the user or fixed secure object. The tether should be minimum length to preclude damage from tethered tool “free swing”.

A.17 Tote Tray - A device for storing/carrying/transporting tools or equipment in a secure manner to prevent inadvertent dropping: i.e., a tool holder, an apron with pocket rings to which tools can be secured. Tote trays with lids will have the lid secured to the tote tray body.

Please View Our (FOD) Signs And Frames Page

Article Highlights

Promotions

FOD Damages to 737 Flying Controls

Original post courtesy of Aerossurance.com

The Incident
During routine maintenance of a Boeing 737-838, engineers found metal filings next to the stabilizer trim cable drum in the forward electronics and equipment compartment (located underneath the flight deck).

737 Control Schematic (Credit: TAIC)

While investigating further they found what they described as a cleaning ‘rag’ had been trapped in the windings on the forward cable drum.

The Debris (Credit: TAIC)

This foreign object had caused the stainless steel cable to bulge outward, contact the softer aluminium cable guides and the resulting wear had created the metal filings.

Bulged Cables (Credit: TAIC)

In places the cables had worn right through the tubular aluminium spacer and had started to wear through the harder steel bolts that run through the spacers.

able Guide Steel Bolt Damage (Credit: TAIC)

The Investigation
In their investigation report, issued in March 2015, TAIC state, based on lab tests of the material, that it was “highly likely” the debris originated from the Qantas Sydney maintenance hangar. The ‘rag’ was actually a cellulosic or paper-based fibre and polypropylene material, consistent with one of the disposable tear-off paper roll products used at Sydney.

TAIC concluded that:

The integrity of the aeroplane’s stabiliser trim system manual control was compromised. Whilst considered unlikely, there was the potential for the stabiliser trim system manual control to become jammed or at worst disabled if a cable severed.

Another Incident
Interestingly Melbourne and Auckland sites use fabric rags which, due to their greater robustness, have a far greater potential to cause FOD events, such as jamming bell cranks, or jamming landing gear uplocks. The later was demonstrated by a subsequent incident involving a Jetconnect aircraft that had undergone maintenance at the Qantas Melbourne maintenance hangar in September 2013. TAIC did not investigate this incident but do comment on it:

On 11 September 2013 a Jetconnect B737-838, registration ZK-ZQC, was involved in an incident that occurred during a flight to Wellington. The aeroplane had departed from Melbourne, where it had recently had maintenance carried out on the landing gear. After departing Melbourne the flight crew had difficulty raising the right main landing gear. The right main landing gear initially retracted but did not stay up, falling back down once the gear selector was moved to the off position. When the crew reselected the gear lever to the up position, the right main gear retracted and stayed up. After the aeroplane landed at Wellington the ground engineers inspected the landing gear and found a rag wrapped around the right main landing gear uplock assembly.

Qantas… conducted a safety investigation into the second incident, which found that the rag had been used by an engineer to protect against an accidental head strike on the uplock during a maintenance task in the right main wheel well area. The rag was subsequently left on the uplock assembly after the maintenance task was completed, and it interfered with the retraction of the right main landing gear during the next flight.

Safety Lessons
TAIC make no recommendations but state, fairly self-evidently that the key lesson is that:

… all personnel must take care not to leave anything behind inside an aircraft after completing maintenance or cleaning tasks, especially in areas or near systems critical to flight safety.

This incident does demonstrate that in addition to control of tools other items, such small components, reels of lock wire and consumables, also need to be controlled. One such case involved a bearing element from a roller bearing that jammed a Power Control Unit (PCU) on a Turkish B737-400 in 2009.

The landing gear incident, which is unlikely to have happened with paper based wipe, illustrates the downside of fabric cloth / rags.

FOD Damages to 737 Flying Controls Click To Tweet