NASA’s Aviation Safety Reporting System released an alert bulletin May 19, 2020, warning the FAA of a possible problem connected to alcohol wipes in the cockpit.
The ASRS report that spurred the bulletin was submitted by an airline captain: “At cruise, smelled like wire burning, put masks on, then visible smoke was coming from pedestal. Flew barber pole until approximately 15 km, landed, shut down airplane, no more visible smoke, but still bad smell in airplane. Kept masks on and opened windows. Opened door, smell dissipated, deplaned. Mechanic found fire/overheat system circuit breaker popped wires were burnt. He told me Maintenance Control advised him this has happened to several airplanes. They believe alcohol from wipes is shorting out wires.”
In the bulletin, Becky L. Hooey, director of the NASA Aviation Safety Reporting System, notes that “We do not have sufficient details to assess either the factual accuracy or possible gravity of the report. It is our policy to relay the reported information to the appropriate authority for evaluation and any necessary follow-up.”
Perhaps it’s not the alcohol itself, but the water that is used to dilute it that’s the problem? 100% alcohol is not commonly available. Usually it’s between 50 – 70%
I’ve been an A&P for over 40 years and a ham radio type / electronics tech / retired USAF for over 60
I’d be careful recommending the use of WD-40 as an electrical contact cleaner. I’ve ruined more than one switch that way trying to lightly lubricate the mechanical part. WD-40 displaces water but leaves a slight oily residue behind … that’s why some people use it for a lubricant. For a while, it DOES work that way especially on the mechanical parts of a stubborn switch. But the electrical parts are a different story. If you want to clean contacts … use contact cleaner/lubricant. If you then want to lubricate the contacts, use DO NOT USE WD-40 ! Don’t do it ! That’s why my add on cabinet on my roll around tool box has oodles of different cans of sprays in it … there’s a purpose for each one.
For grins, I just went out to my work bench and sprayed a bunch of WD-40 onto a surface and tried to see if I could get an ohmmeter reading across it … no way. But just because it doesn’t conduct electrons doesn’t mean the oiliness isn’t there. In fact, the paper I sprayed it onto has been wet for >30 min. If that oiliness got across a circuit trying to conduct serious current, I’d bet some smoking might go on because the oiliness would prevent proper conduction of the current.
Quick vaporizing pure alcohol would be OK as per Jeff Owens excellent analysis / experience.
Now then … GET READY !!! I’m sitting here typing, look over at my cup of coffee and the ohmmeter sitting nearby and decide to dunk the probes in. Guess what … I saw a high resistance of ~25K ohms with the probes 1″ apart. VERY telling !! Jeff is right. All you’se pilots out there … keep your coffee away from the switches.
Finally, on EXTERNAL contacts, I use CorrosionX to alleviate corrosion. It seems to work where WD-40 doesn’t. In fact, if you read the instructions on the can, it says it’ll work on electronics. I wouldn’t use it on a sealed item like a potentiometer but I spray it on battery terminals and the like all the time.
There is no way anyone can convince me that the vapor from perfume somehow migrated into a brake switch … NO WAY. Suburu did something wrong during the manufacturing process of the switch. Maybe they used WD-40 ?
Forgot. Alcohol wipes are meant for surface cleaning, not for squeezing the “juice” into the innards of things. The ones I’ve used aren’t that wet anyhow. And even if water was used as a carrier, it too would evaporate over time. Might cause corrosion in volume but I doubt it’d be a problem.
I’ve seen pics of airplane interiors being sprayed down with liquid vapors … now THAT is something I’d worry about … especially in a cockpit and in the hands of a less than qualified person.
This whole reaction to COVIC-19 is getting ridiculous!
Larry, all good points.
I usually drink the alcohol while in flight…just kidding (I am surprised no one beat me to that!).
Addiction to the drug alcohol has always been a chronic problem in the aviation community.
Very hard to believe. Perfume vapor entering a switch? A little damp alcohol wipe pad getting into concealed wiring dissolving insulation and causing a short? No offense, guys, but I just don’t believe it. I’ve been an electronics tech and engineer for 60 years in radio and TV broadcasting, and never, never had any issue with alcohol wipes or swabs used for cleaning any delicate apparatus. I’ve used WD40 to clean hot switch contacts and internals of potentiometers and it never flared up. Ordinary 50% isopropyl drugstore alcohol is excellent for cleaning and disinfecting hand-touched surfaces, including switch actuators, keyboards, etc. Obviously, you don’t pour the bottle out on the electronics and drench it, you just gently wipe with a moist pad of the stuff. This case needs further investigation and proof by NTSC before I’ll accept the speculation. Regards/J
Agree, I also found it hard to believe. Nevertheless, Subaru found it believable enough to recall almost 2.5 million cars worldwide to replace the brake light switch. On the recall notice, it specifically mentioned fumes from perfumes, and mentioned it first. My first response was “Are they kidding?” Obviously, they weren’t. Dear Bride took her Forester to the local Subie dealer, they changed the switch and washed the car, for free. Somehow I doubt they did this purely out of the goodness of their hearts.
I too have used alcohol and alcohol based solvents to clean electronics components for years, and never once had a problem.
Some of these chemical interactions can be extremely obscure. If you read the history of the SR-71, Skunk Works was having problems fabricating many of the titanium parts, they were cracking. Turned out the impurities in the tap water used to wash the parts was the culprit – switching to distilled water cured the problem.
Stay safe!
“Alcohol doesn’t conduct electricity because it’s a covalent compound. … Hence alcohol molecules are not ionized in water because the bonding within these molecules is strong enough to resist the breaking of their bonding by polar water. So, these compounds are not splitting in to ions,hence conductivity is zero.” (found online)
Having said that, impurities of some kind might conduct electricity. The determination, especially after a ‘fire’ or destruction from a short would require a very careful chemical analysis, not wild speculation about perfume vapor. I would like to see exactly what real analysis was done by Subaru. Blaming a manufacturing defect on ‘fumes’ seems like a coverup.
In the Navy we used alcohol frequently to clean contacts on SONAR gear. Pure ethyl alcohol (It evaporates without residue.), not drug store alcohol, in which the percentage not alcohol is water.
Also having worked on many aircraft in my post Navy career, the biggest contaminant causing cockpit problems is COFFEE.
Hogwash? Tell the NTSB. Subaru recalled 2.3 million cars worldwide, 1.3 million in the US alone for defective brake light switches which were damaged by a) silicone in cleaning fluids used in the cars and b) vapors from PERFUME (no less) worn by female passengers.
Wife’s Forester was one of them, so here’s personal experience, not some facebarf rumor.
The pilots had a problem and reported it, maintenance said they had seen this before. Something IS going on, and it would probably be a good idea to find out what before there’s an in-flight fire or a crash.
Hogwash! Alcohol vaporizes the second it’s wiped onto a surfaces and is used to clean wiring and components in the computer industry. The only way this can damage a wire is if the wire coating is a plastic that melts using alcohol but that would be noticed at the time of cleaning.
I use this stuff – no alcohol….does a great job.