Low Vacuum Light - False Positive

Greebo

Greebo

N9017H - C172M (1976)
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Retired Evil Overlord
If an airplane has a low vacuum light and a vacuum gauge, and the low vacuum light is giving a false positive (ie the pump has been tested and is ok and the gauge indicates that the vacuum pressure is ok... well is it technically legal to just "ignore" the low vacuum light? What about to advise others to do so?
 
well when it really takes a crap, the light isn't going to change, and you probably wont notice it until just before you are a smoking hole in the ground, so id vote for getting the light fixed. I let the others figure out if its legal or not to fly with it malfunctioning
 
Oh it will get fixed - the group in question always takes good care of the plane and doesn't skimp on maintenance. I just have my doubts about them saying, "Just ignore it" for now. I think at a minimum it should be plaquarded.
 
ah yes, the good ole "failed in flight" ruse until maintenance can get done. its not anywhere near required equipment so you can fly without it operating, as long as its placarded.
 
Greebo said:
Oh it will get fixed - the group in question always takes good care of the plane and doesn't skimp on maintenance. I just have my doubts about them saying, "Just ignore it" for now. I think at a minimum it should be plaquarded.
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Look in our POH and see if the light has an "R" beside it, then you will know if it is required for flight.
 
14 CFR 91.213 requires that any malfunctioning/nonfunctioning items be dealt with before the next flight. We know that a vacuum warning light is not part of 91.205, but as Bill said, if the light is an "R" item, the airplane may not be flown until it's fixed. If it is not an "R" item, then you must either repair it, or disable/placard it before the next flight. In any event, it is not "technically legal to just ignore the low vacuum light."
 
Thats what I suspected Ron. Since I haven't been actively flying lately, I am not going to worry about it, but if I were going up any time soon, I'd be taking an INOP sticker with me to stick on that light just to cover my own tush.

*sigh* The club plane instructor is a nice guy - and he's got a LOT of time in a lot of birds - but he's just a bit to cavalier about some of the regulatory stuff for me.
 
Greebo said:
If an airplane has a low vacuum light and a vacuum gauge, and the low vacuum light is giving a false positive (ie the pump has been tested and is ok and the gauge indicates that the vacuum pressure is ok... well is it technically legal to just "ignore" the low vacuum light? What about to advise others to do so?
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If you use a little piece of duct tape over the light it is not a problem, unless you get caught. Oh wait that was a thread from somewhere else?? :eek::goofy:

I am currently having this problem. The light will not turn out for a while, we cleaned up the swtich but it is still there. I have to order an upgrade kit for my standby vacuum anyway for AD compliance so I am ordering the replacement light switch as well. In the meantime the light is marked INOP and I do have a vacuum guage that gets checked a lot. When the AI needs to be overhauled I am going to also replace it with one that has the vacuum flag on it. Having faced a vacuum failure on a moonless VFR night I never want to face it while in IMC.
 
Greebo said:
*sigh* The club plane instructor is a nice guy - and he's got a LOT of time in a lot of birds - but he's just a bit to cavalier about some of the regulatory stuff for me.
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That might just bite a club member, as supposedly the FAA is stepping up on ramp checks, and I've heard that inop equipment is one thing they are checking on. Our club instructors had a quick tutorial on this a month back, that is why I knew about checking the POH to see if the inop equipment is an "R' item. We also discussed how to put non-"R" equipment on a deferred MX list.
 
Just change over to using that light as the annunciator for the leading-edge heat strips for deicing, OK?
 
Let'sgoflying! said:
I thought you had to do more than just a placard.
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Our club guy (left seat in an RJ is his day job) says you must put the item on a deferred MX list. :dunno:
 
i think thats only if you have a Minimum Equipment List?
 
Let'sgoflying! said:
I was thinking a logbook entry
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Per 91.213(d)(3)(ii) and 43.9(a), the logbook entry is necessary only if "maintenance" is required to deactivate the inoperative item.

BTW, I keep a Dymo labelmaker in my hangar, although I'm beginning to consider keeping a few pre-made "INOP" labels in the glove box.
 
Ron Levy said:
14 CFR 91.213 requires that any malfunctioning/nonfunctioning items be dealt with before the next flight. We know that a vacuum warning light is not part of 91.205, but as Bill said, if the light is an "R" item, the airplane may not be flown until it's fixed. If it is not an "R" item, then you must either repair it, or disable/placard it before the next flight. In any event, it is not "technically legal to just ignore the low vacuum light."
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Ron,

What about disconnecting inop avionics? One of our planes has an inop ADF. The gauge is placarded, the radio portion is not. I've heard that to be strictly legal, we'd have to unplug the ADF entirely. However, the compass was swung with the ADF on, so at my CFII's direction I've always turned it on. Do we need to disconnect it and re-swing the compass, or is it OK with just the placard?
 
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