Clarification on Supervising a Non-Certificated Person Working on Aircraft

Customers have asked me if they can perform work on their aircraft under my supervision and if I needed to be there to direct them while doing the work. They have told me that other mechanics have allowed them to do work while that mechanic was not present. They also said that they could just send that mechanic a picture of the finished work they had completed and that the mechanic would then sign the work off in their log books. They went on to state that their mechanic had worked with them in the past and trusted their work.

I have researched the Internet and the FAA’s Chief Counsel database looking for a Legal Interpretation of this regulation, without finding any worthwhile results.

This is addressed under FAR 43.3(d). 

43.3 (d) A person working under the supervision of a holder of a mechanic or repairman certificate may perform the maintenance, preventive maintenance, and alterations that his supervisor is authorized to perform, if the supervisor personally observes the work being done to the extent necessary to ensure that it is being done properly and if the supervisor is readily available, in person, for consultation. However, this paragraph does not authorize the performance of any inspection required by Part 91 or Part 125 of this chapter or any inspection performed after a major repair or alteration.

Here is my my interpretation of this regulation

There are three parts to this regulation that must be met in order for the supervising mechanic to be in compliance.

Part 1 reads:

if the supervisor personally observes the work being done

To personally observe the work is self explanatory. It means the supervisor himself and no other person.

Part 2 reads:

to the extent necessary to ensure that it is being done properly

This is a bit more vague and somewhat subjective. It means that if the work performed consists of multiple tasks or steps (which most work consists of), then the supervisor must personally observe each of those steps that make up the entire process from start to finish. The reasoning behind this is that once a person has completed a step and moved to the next step, the prior step cannot be observed (in most cases) by the supervisor to ensure that it is being done properly.

If the supervisor can observe the finished work and determine, by observation alone, that the work was done properly, then this would satisfy the requirements of the regulation. IE a person assembles a simple piece by drilling holes and installing a few rivets. The supervisor inspects the piece and verifies that it meets the dimensions and that the rivets are properly installed and the correct type/size. By this inspection he can satisfy the requirements of the regulation.

Another example might be when a person installs a propeller. If the supervisor only personally observes the finished work by inspection of the propeller after it has been installed and safety wired, then he could not, to the extent necessary, ensure that it (the installation of the propeller) was done properly. The reason that this would not satisfy the requirements of the regulation is that there are multiple steps to installing a propeller, some of which are critical to the safety of the finished process.

1. Inspection of the crankshaft flange, thread inserts and attaching bolts,

2. Correct indexing of the propeller to crankshaft flange (if the propeller can attach in more then one position)

3. Torque requirements of the attaching hardware (dry or lubricated threads, stretch fit, degrees to rotate, etc)

4. Torque setting and correct procedure to apply torque

5. Torque wrench used.

Inspection of the completed work alone would not reveal that the above 5 steps were done properly and therefore would not satisfy the requirements of the regulation.

Part 3 reads:

if the supervisor is readily available, in person, for consultation

This is self explanatory. The supervisor must be available, in person. The current definition of in person is:

Merriam-Webster Dictionary: “in one’s bodily presence “

Cambridge Dictionary: by meeting with someone rather than talking on the phone, emailing, or writing to the person. This basically means being physically present.

In summary. The supervisor must observe those steps during the work being performed that cannot be observed by the finished work alone, and he must be physically present and readily available (on site) while the work is being performed. Can the supervisor meet the requirements of the regulation without being physically present? No, he cannot. Can the Supervisor inspect just the finished work that was performed? Not likely, unless the task consists of only a few simple steps.

If a mechanic trusts another persons work, does this entitle that person to perform work that would normally require a certified mechanic to perform? Does this “trust” alleviate the Supervisor’s responsibly from complying with the above three requirements of the regulation? The answer is no to both of these. There is nothing within this regulation that allows the Supervisor to waive his responsibilities just because he “trusts" another persons work.