In the previous article I ended with a reference to the Civil Aeronautics Act of 1938. I pointed out how it has a paragraph setting the conditions for an airworthiness certification to be issued to an aircraft in 1938.
Airworthiness Certificate (Civil Aeronautics Act of 1938)
Section 603. (c) ……. If the Authority finds that the aircraft conforms to the type certificate therefor, and, after inspection, that the aircraft is in condition for safe operation, it shall issue an airworthiness certificate.
Just a few years ago the FAA added information in 14 CFR part 3 which includes, under the heading Definitions.
Airworthy means the aircraft conforms to its type design and is in a condition for safe operation.
Not exactly the same words but the intent counts. I think addressing some of what ‘type design’ means to the average M1A1-mk1 Aircraft Mechanic today is in order.
It seems very simple to say, “If it meets the “type design, it’s good to go”. After all, the aircraft was built by a company according to a Production Certificate. What could be wrong with that?
If certain aviation products were built in the last 6 to 7 decades, it has a Type Certificate Data Sheet (TCDS). Both the Type Certificate Data Sheet and the Production Certificate require the aviation product to meet standards which are documented in both of those certificates.
Let’s look at that statement a little closer.
If the aircraft just rolled off the assembly line, it would be an easy task to ensure it meets the TCDS. After the aircraft goes through customer completion it is still an easy task. All the required paperwork would be readily available for review and inspection. That’s where the easy part stops.
Even after just a few years in service an aircraft may not conform to the “type design”. As the aircraft operates, more parts are changed, and more modifications are incorporated. It has the potential to move further outside the “type design”. Consider an aircraft and the parts installed during its lifetime.
How does the installer/maintainer know which part is for this specific aircraft?
Even down to the specific serial number aircraft?
Not too many years ago, the FAA started requiring an aviation manufacturer to develop Instruction for Continued Airworthiness (ICA) for their products. The requirement is found in 14 CFR 23-25-27-29.1529. The requirement for ICA’s can be found in all the certification regulations for aircraft, engines, manned free ballons, and propellers. Aviation manufacturers can’t get a Production Certificate until they have the ICA in place or a plan to have the ICA in place when the aviation product is offered for the market. Of course, the ICA includes more than the maintenance manual.
The maintenance manual is just one of several documents which make up the ICA. There are the Service Bulletins, the Standard Practices Manual to name a few. There is one more, the Illustrated Parts Catalog (IPC).
The illustrated parts list/catalog (IPC) plays an essential role in the ICA information suite of documents. The IPC is issued by the certificate holder/manufacturer. The IPC is part of the necessary information to ensure the aviation product (aircraft in this example) meets the “type design”.
Based on this concept of how the IPC is an integrated part of the information associated with the aircraft, the IPC is an extension of the TCDS. Failure to comply with the ICA, including the IPC, can make the aircraft unairworthy. Failure to install the correct parts would result in the aircraft no longer meeting the “type design”.
The IPC is not just a book with pictures. It is not just a book used to order parts and find part numbers. It identifies, as well as pre and post bulletin modification, to those specific serial number aircraft. There are some parts allowed to be installed on that one aircraft and some parts are NOT allowed to be installed. All of which is the job of the installer to determine. It will require research to ensure each part is compatible with the specific serial number aircraft. There may also be a limit to the parts based on other parts installed on the aircraft, the pre and post modification limitation.
If a modification is made, there may be a limit on which parts are compatible with the modification. On new aircraft that is an easy task. Not so much on an aircraft which is only a few years old.
Imagine a fifty-year-old airframe. Now try to verify the modification and alterations on the airframe. If it is a private aircraft, you may be able to get some documentation on modifications and alterations. Probably not going to happen.
Most records are not required to be kept for more than a year. Some are required to be kept until the work is repeated or is superseded. If there are life limited parts or total time information, that should be retained. A list of applicable Airworthiness Directives (AD) should be retained. For a full list of what needs to be retained, look at 14 CFR 91.417. Most readers will find it very interesting to say the least.
Now, where does this leave the M1A1 mk1 mechanic in determining if the aircraft meets the type design criteria? It would require a review of each item installed on the aircraft, if the items have a data tag, reading the part number and comparing it to the IPC. A long a laborious task to say the least. There is the necessity to consider any modification to the aircraft also.
For those maintaining a Bonanza built in 1964, sold to three doctors in sequence and a lawyer over the years, now it is owned by the family which are trying to keep it airworthy for one of the grandchildren of the lawyer. Of course, they are not sure where the records are for the aircraft. They just want it to be available. They are looking for an annual inspection to be conducted, for the grandchildren.
The mechanic needs to determine if it meets the type design. The aircraft has a TCDS with 56 pages with the original issue date of December 1956 to the latest issue of October 2022, with 27 different models. Over twenty-three pages of items which are “Specifications Pertinent to All Models” and eight pages of “NOTES”. After making a determination of what is physically on the aircraft, now there needs to be a comparison to the current IPC to see if the parts are compatible with all parts of the TCDS.
Haven’t even considered the research of applicable Airworthiness Directives.
There is more to being that M1A1 mk1 mechanic than turning wrenches on the aircraft. Research and more research spending hours looking at different documents and available records. All in an effort to ensure the aircraft is airworthy.
Then the owners will be gob smacked when they are told the cost to comply with the annual.
This is only the beginning of what is required to ensure an aircraft meets the “type design”. I’ll let you consider that as I move on to the condition of “Safe”. That is another long and tortious trek. I’ll cover it next time.
Jeffery Howard
Stay Safe, Stay Strong and Stay Professional
Comments