Undocumented Aircraft Repairs

Unintentional Damage Examples 

Hanger Rash 
Hanger Rash is a common undocumented damage. Which can easily lead to an undocumented repair. Let’s say a lineman was re-positioning aircraft to get ready for the next day's departures when he accidentally clips a position light against the hanger door. He realizes this and sees that it pulled the light out from the wings fiberglass mounting surface just slightly. He, who is mechanically inclined but not authorized to do a repair, gets his tool box and removes the wingtip and institutes a substandard and illegal repair to prevent anyone from realizing that any damage occurred. Now he believes he has done the right thing, after all he has saved his company from the time and embarrassment associated with dealing with this problem and the customer can fly his plane the next morning. This is obviously a rare occurrence but none the less it happens all too often. This is an example where undocumented damage becomes an undocumented repair. 
 
Bird Strike 
Bird Strikes are even less common but do pose a real issue with undocumented damage. A pilot is on short final when a small flock of birds is startled and fly into his path. He receives a strike against his wing's leading edge and it dents slightly. This pilot who is an A&P looks at the damage and decides that it is negligible and does not report the damage to the owner. This bird strike was later seen by the owner and he asked the mechanic about it. The mechanic told him the story and said it was a negligible dent and wouldn't affect the flight characteristics of the aircraft. And besides "you don't want a damage history". Well this is entirely all too common. A mechanic advises his client to not document or repair negligible damage due to its effect on aircraft value. This is simply not good advice. At the end of the day the aircraft must conform to its original type design and any negligible damage is not part of the type design. I know what you’re thinking and the answer is "It is a very narrow line to walk but use your judgment on what should be repaired and what really is negligible." Regardless it must all be documented.   
  
Hard Landings   
This is common among training aircraft. The reality is that aircraft are very very tough. Sometime though, not tough enough. Some of the hidden damage could be overlooked for several inspection cycles and sometime maybe not discovered at all. It is important to make sure that when you experience a hard landing that you have the aircraft thoroughly inspected SPECIFICALLY for that damage. Do not wait until the next 100 hour and say "Oh yeah, I had a student really drop this one on its nose last month. Could you look for any damage?" What happens here is that the mechanic is performing a 100 hour inspection, not a hard landing inspection. The inspection should always equal the suspected damage. This is why when you suspect any damage you should inspect for that damage immediately. Don't put it off just because you don't see any obvious defects.    

Un-Ethical Practices To Reduce Damage History 
  
Believe it or not it happens. This is when a person provides substandard services, illegal repairs, when an owner "Fixes his plane", and when a person puts the future aircraft value ahead of safety and the rule of regulatory compliance. Where the events and scenarios above were fictitious these will be directly from my experience as a mechanic.   
   
Cowling Alteration - Substandard Service   
I was working at a facility where a light twin had been grounded for being un airworthy. The aircraft had some major issues but could be easily repaired. One of the damaged components was the aft mounting plates for the engine cowlings. The repair was completed and the mechanics moved on to the next issue. During this maintenance the aircraft received some hanger rash and a new elevator was required. This became the major issue and once resolved the aircraft was signed off as airworthy but the repair to the cowling was never documented. The service the owner received was not to the standards required by the FARs and the owner should have expected these mechanics to do a better job. Be very careful when hiring mechanics as they are not all equal.   
   
Ice Shield Repair - Illegal Repairs   
When I worked for an airline I was involved in a squawk that required a repair or replacement of a fuselage ice shield. The replacement part was in the computer inventory and I removed the damaged component. The question that was raised in this case is what happens if the replacement part is not actually in stock? Well unfortunately the broad answer is not so easy. My answer is you cannot reinstall that damaged item even if it was deferrable due to the fact that the steps in properly documenting a maintenance event is to record the removal of the damaged part. Once you have committed to removing the damaged part it becomes un-airworthy and cannot be re-installed regardless of its deferability in the MEL.

The actual events that occurred were as follows:

I noticed a significant impact to the ice shield and wrote it up as being damaged.
The inspector told me to replace the ice shield.
I confirmed the availability of the replacement part in the computer inventory.
I removed the damaged part and prepared the surface for the replacement part.
I sent for the new part and was told that we didn't have it in stock. (Inventory Error)
The Inspector said to re-install the old one.
I refused.
He said to repair it.
I researched the SRM and found that we did not have the proper facility to repair it.
He said to just put some 5 minute epoxy in the area and sand it down and paint it.
I walked away.
He found someone else to jeopardize their standards and the aircraft departed on time, illegal, and unairworthy.
This is a common practice and is overlooked by many people and can be considered as SOP for some maintenance facilities. It is the responsibility of the mechanic to stand firm on his knowledge of the regulations and question the actions of his supervisors if the policy is to circumvent the rules to make an on time departure.
  
   
Owner Repairs - Propeller Installation - Improper Authority   
This is a case of blatant regulatory violation. A pilot who tied his aircraft down at the field where I worked for a summer was putting a different propeller on his aircraft. This pilot did not have a basic understanding of the regulations as they applied to a pilot’s ability to perform maintenance. His answer to my question about his authority to replace his propeller was that it was "within his ability." What he knew, but didn't want to divulge was that his abilities had nothing to do with the authority to perform a propeller replacement. First a pilot is limited to preventative maintenance as it is listed in FAR part 43 Appendix A. Furthermore this pilot installed this prop without any guidance or maintenance manual. This is totally wrong. The pilot said that he only needed to make an entry into the logbook stating that this propeller was installed on this airframe. I don't believe the pilot knew the significance of the yellow tag or if the propeller even had one. To this day I still don't know if the pilot even installed a prop that was type certified for the aircraft. This is a case where undocumented or improperly documented changes can impact the safety of flight, and it still happens.   
   
Undocumented Repairs - Former Repair - See Photo   
During a prepurchase evaluation I discovered a serious issue with an aircraft's fuselage structure that was undocumented. the aircraft had received minor damage a few month prior and the damage that was recorded was apparently done so that the repairs would not constitute substantial damage in so far as the reporting requirements to the NTSB. What was repaired but not documented to circumvent the required reporting to the NSTB was a replacement of a fuselage former. This former was initially overlooked by me until I had photos developed and I had an opportunity to study the photos of the tailcone section. I suspect the reason this repair was left undocumented is because it would have required a filing of an aircraft accident to the NTSB and filing of a major repair to the FAA which in turn would reduce the value of the aircraft. The repair was done correctly and the aircraft would be worth more if the repair had been documented. Partly because I would not advise my client to purchase this aircraft because of this undocumented repair. Remember "Where there’s smoke there’s fire." If the owner was willing to hide this, what else was he willing to compromise. He obviously doesn't want to fly this airplane anymore. Why else would he be selling it? So be careful when preparing to purchase an aircraft and be sure your mechanic who is reviewing the aircraft is very meticulous. This could be the difference in hundreds of thousands of dollars.   
   
Poor Record Keeping - Keep Your Work Orders 
As a matter of civil liability repair stations do not like to keep work orders any longer than they have to. Be ready to question any facilities that do not want to make copies of the work orders for you records. The reason for the record keeping limitations is not to reduce the responsibility and liability of the repair station. it is to reduce the burden of storing and archiving the records associated with the complexity of aircraft maintenance operations. The FARs provide a two year record keeping requirement for the repair stations after which most repair stations prefer to destroy these records on the grounds that the are taking up space when in actuality they are destroying these records often to eliminate any liability. This is an issue that should be addressed by the regulatory authorities and should be considered a top priority. I will hear from the repair station owners on this one, but the reality is if you are providing proper maintenance and recording the maintenance your facility performs, then the records would only support your defense. As an owner it is your responsibility to ensure airworthiness. this includes the continuity of your records which is what supports your claims of airworthiness. I would advise to all aircraft owners to make sure that the facilities that provide their maintenance properly and thoroughly document the maintenance that took place on each visit.