Hi all,

I sat the CASA CPL Air Law exam recently and was a bit perplexed when I got a question wrong regarding the maintenance a pilot is permitted to carry out under CAR Schedule 8. The question focused on maintenance of spark plugs on a Class B aircraft.

The question was to the effect of:

"can pilots do the following:

- Remove and adjust the gap on the spark plugs?"


CAR 1988 Schedule 8 specifies a pilot may do the following:

12. "Replacement, cleaning, or setting gaps of spark plugs".

The thing is that it appears CASA and I both agree that "removal" is not the same as "replacement". For example, line 19 and 20 of Schedule 8 specify "removal or replacement of equipment used for agricultural purposes", and "removal or replacement of glider hooks". It implies that removal and replacing are two different things, of which I agree.


Given this logic, I answered "no, the pilot can't do that" as my thought process is that you can't just remove the spark plug - you must replace it (one less spark plug obviously leading to a loss of efficiency and redundancy). However, I got the question wrong.

Could anybody possibly shed some light on this/care to share their opinion?

I think maybe you are over-reading the question. To me, replacement implies that removal occurs first. If I told you to replace a book on the shelf, you must have removed it in the first pace. A pilot can remove a spark plug, clean and reset the gaps, and then replace it.

By the way, Schedule 8 says that the pilot can legally do a number of things that would, in practice, require some previous experience and/or knowledge, such as setting spark plug gaps, removing and repairing tires, and greasing wheel bearings. I guess it was written in the days when it was left to you to exercise some common sense.