Ask the DAR

Do mandatory service bulletins apply to homebuilts?


Question: As a DAR, where do you stand on mandatory service bulletins from kit manufacturers? Do these have the force of law?

Answer: Good question and one that gets bandied around quite a bit.

When it comes to mandatory service bulletins for Experimental/Amateur-Built and Light Sport Aircraft there are varying opinions. We know that MSBs are not legally binding as far as the FAA is concerned-even for certified aircraft. An owner can decide if he wants to comply with MSBs.

Only Airworthiness Directives (AD) are binding. And because ADs are written against a type certificate, and E/AB and LSA don’t have a TC, what are we to do? In other words, the kit manufacturer does not have the option of getting the FAA to issue an AD.

The only other thing left for the kit manufacturer is the mandatory service bulletin, which we have already stated are not legally binding.

Because the MSB is not legally binding, does one have to comply?

Well, technically, no!

But lets consider this: The manufacturer would not issue this bulletin unless there was a real and prevalent safety problem, whether that comes from the original design or from knowledge amassed as a particular aircraft gains field experience-maintenance-related, in that respect.

Are some MSBs issued primarily for the protection of the manufacturer? Of course. But they are also issued to save you from a possible accident or problem that may cause you or someone else loss of property or even a life. Each and every MSB must be evaluated by the aircraft owner and/or builder as to its relevance.

In a court of law, attorneys may use anything that is in their favor to make the case for a client. Obviously kit manufacturers would like everyone to comply, both for your safety and for the comfort level of their attorneys. This is why most of these service bulletins are labeled mandatory.

A DAR has some leeway as to what can be accepted or rejected regarding SB and MSB compliance. If the inspector is of the opinion that the MSB was indeed issued just for protection of the manufacturer, then he can issue an airworthiness certificate without compliance of the MSB. He would be doing you a great disservice if he didn’t at least talk with you at length about the purpose of the bulletin. Remember, when you present the aircraft for airworthiness certification, you are stating that the aircraft is in a condition for safe operation. Can you honestly make that statement if you know there is an outstanding safety related service bulletin?

There are MSBs out there that I definitely would not sign off on without specific compliance. There are a few that I feel are somewhat unnecessary if the aircraft is built in accordance with the plans. If I elect to issue an airworthiness certificate to an aircraft where an MSB is not complied with, I will at a minimum require a signed statement from the builder that he is aware of the bulletin, and he has decided to either not comply or to comply with some alternative method. If he has elected not to comply, I want the reason for this decision from him in writing.

If the applicant and I disagree on the matter, I can simply deny the certificate and he can take the matter to another DAR or the FAA and try to convince them. Now keep in mind that if I deny the certificate, the reason for denial goes out immediately to every other inspector in the U.S. So don’t think this is something you will hide from the next inspector-at least not if he’s paying attention. And you should also know that you are still responsible for the DAR fee. The fee is for the inspection, not for the certificate itself.

Obviously, this doesn’t happen often. As a matter of fact, I have never denied an airworthiness certificate on these grounds since I began doing this 11 years ago. You just need to be aware that it could happen.

Please send your questions for DAR Asberry to [email protected] with Ask the DAR in the subject line.


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.