Let's say you discover that your landing light is inoperable during the preflight. Your aircraft doesn't have a MEL, so you follow 14 CFR §91.213(d). Assuming you do everything else required (placard, etc.), would placing a collar around a circuit breaker be considered deactivation?

If not, is there anything that a private pilot can do that would be considered deactivation?

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    $\begingroup$ The humorous absurdity of pulling & collaring a breaker (interrupting the circuit) for a failed landing light (usually because the incandescent filament has burned out, interrupting the circuit) is not lost on me. Though on a serious note, if we're talking about a fault in a HID landing light system or LED landing light the potential failure modes certainly warrant "preventing the operation" of the system until you know what caused the fault... $\endgroup$
    – voretaq7
    Commented Dec 28, 2013 at 8:36
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    $\begingroup$ It does seem a bit absurd. I asked this question because it's one that seems to come up in checkrides. During my checkride I was asked what I would do in this situation. I answered that I would collar the circuit breaker, and the DE told me that would not be enough and I would have to have a certified mechanic repair the light or disconnect the power to the circuit breaker to be legal. I didn't argue, but I'm pretty sure he's wrong and the collaring is deactivation. $\endgroup$
    – kevin42
    Commented Dec 28, 2013 at 15:33
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    $\begingroup$ I would think collaring qualifies as deactivation too - certainly as lnafziger pointed out it's what manufacturers recommend, and I'm pretty sure it's what airlines do for non-critical equipment that needs to be "tagged out" because it's broken. For that matter taping a bent index card cover over the switch so you can't turn it on it would also seem to qualify, albeit a somewhat inelegant solution. $\endgroup$
    – voretaq7
    Commented Dec 28, 2013 at 21:55

2 Answers 2


Based on this Advisory Circular, the answer is yes.

g. Deactivation means to make a piece of equipment or an instrument unusable to the pilot/crew by preventing its operation

Collaring the circuit breaker prevents it from being pushed in, and therefore prevents its operation.

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    $\begingroup$ This is consistent with MEL M&O procedures that in some cases specify doing exactly this. $\endgroup$
    – Lnafziger
    Commented Dec 18, 2013 at 21:24

Per AC 91-67A, there is nothing a private pilot can do:

Deactivation. When an item is “deactivated” or “secured,” or both, the specified item must be put into an acceptable condition for safe flight. Deactivation may involve more than simply turning off a system switch, which does not remove power from the system. Deactivation may involve pulling and securing the circuit breaker and/or removing the equipment. Deactivation of an inoperative system is not preventive maintenance as described in part 43 appendix A. Regardless of the method of deactivation, a person authorized to approve the aircraft for return to service under § 43.7 must make the maintenance record entry required by § 43.9. No person may operate the aircraft without the entry required by § 43.9.

Deactivation of any inoperative component can only be done by someone authorized to do maintenance, and they must make a log in the maintenance records to return the aircraft to service.

This is a change from the previous version of the AC mentioned in the other answer. Collaring a circuit breaker may still be acceptable, but it needs to be returned to service by a mechanic or someone else authorized to do maintenance on the aircraft.


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