Hydraulic Fires

[pelmet]

Within a couple of days of each other, I came across what has to be one of the scariest things that can happen to a pilot, a hydraulic fire in the cockpit. I always try to think of what could one do in such a situation and in cases like this, it almost seems as if you are doomed.

I suppose well before any flight, if one is in control of the maintenance aspect of an aircraft, don't hesitate to ask the mechanic to check and see if any electrical wires are chafing against a hydraulic line.

It is interesting to see what the pilot who survived did in his case......an intentional crash. He also has some interesting recommendations near the end of his story on what you could do as prevention. It could save your life.

https://midwestflyer.com/?p=12924

https://app.ntsb.gov/pdfgenerator/Repor ... l&IType=FA

[Capt. Underpants]

Another scary one. Electrical fire fed by hydraulic fluid.

https://www.planeandpilotmag.com/articl ... mhvXy8TEgo

[pelmet]

Item 34 of the Killer Item Checklist: ask the mechanic to check and see if any electrical wires are chafing against a hydraulic line.

Something that the pilot recommended and that we as pilots should think about.....

"At the initial onset of smoke and/or fire in the cockpit, I should have moved the engine mixture to cut off. In my case, this would have stopped the engine-driven hydraulic pump from feeding the fire. Obviously, I did not prepare my mindset for this event. I just never suspected that what started as a generator failure, could result in the fast onset of a ferocious fire."

You should try posting something useful that could save a life sometime Dash. It isn't that difficult. Lets see if you can come up with something, even a quote from another pilot that could help.

[pelmet]

Another scary one. Electrical fire fed by hydraulic fluid.

https://www.planeandpilotmag.com/articl ... mhvXy8TEgo

Thanks. The NTSB report in the initial post is for this terrible accident but I had not seen the article.

After reading DashTrashes sad post(it is based on a subject from a different thread), isn't is interesting that the last line in the magazine article is....

"And, it should be a reminder for us to tell our mechanics to pay particular attention to the security and condition of aging electrical wiring inside of the aging airplanes we fly."

Beware of who you take your advice from.

[7ECA]

Beware of who you take your advice from.

More reasonable thing I've heard on this forum, in a long time.

[rxl]

I suppose well before any flight, if one is in control of the maintenance aspect of an aircraft, don't hesitate to ask the mechanic to check and see if any electrical wires are chafing against a hydraulic line.

https://midwestflyer.com/?p=12924

https://app.ntsb.gov/pdfgenerator/Repor ... l&IType=FA

Well intentioned advice, I suppose, but really only useful if you happen to be the aircraft owner.
It’s a fundamental practice of aircraft maintenance to inspect for and to prevent the chafing of fluid lines and electrical wiring. Unless you have some specific concern, asking this of an AME is kind of like asking your doctor to check to see if your heart is beating when you are in for a check up.
Finding and correcting those chafing wires and fluid lines will definitely break the chain of causal factors at the earliest opportunity and, in this case, prevent the accident.

[rxl]

No question is a dumb question, especially when it comes to safety concerns.

[pelmet]

Maybe - you should look at it from a different view.... we should just all wear Nomex suits and bail out of our planes at the first sign of trouble. I mean - there is no way to filter out human error 100%

An interesting statement. This is what the T-28 pilot said, which obviously is more suited to certain aircraft in the warbird world....

"I should have worn all of the fire protection gear I listed above, especially the Nomex gloves and Nomex boots."

"If you have any suspicion that there may be an impending inflight fire, obviously turn the DC power off and land immediately if possible. If a suitable landing area is not immediately available, I would recommend climbing to a bail out altitude and turning in the direction of a non-populated area. It gives one time to deal with emergencies, and it also gives one the option to bail out in the event of a catastrophic fire."

I agree.

[jakeandelwood]

https://www.machinerylubrication.com/Re ... ant-fluids

Non flammable hydraulic fluid seems to be out there, looks like in stationary machinery mostly.

[pelmet]

https://www.machinerylubrication.com/Re ... ant-fluids

Non flammable hydraulic fluid seems to be out there, looks like in stationary machinery mostly.

Thanks, as far as I know, the two mentioned aircraft would have had the standard Mil-5606 hydraulic fluid. Airliners use something called Skydrol. Nasty stuff to be around(we once left a cargo plane quickly because of a leak). But the nasty stuff may be your best friend in terms of it being much less flammable when you have a fire or arcing.

[boeingboy]

I guess most people missed the extreme sarcasm in my last post.....

On the subject of Hydraulic fluids - 5606 and Skydrol are NOT interchangeable. They are completely different animals....however - if the smaller guys want a safer fluid all you have to do is switch to Mil-83282. It is completely identical and interchangeable with 5606. The only difference is 83282 has a much higher flashpoint.

All brought to light here:
https://en.wikipedia.org/wiki/._Flight_420

You can search for the report if you like. The Wikipedia page is very simplistic and has errors....but you get the jist of it. There were many factors, part of the issue was the intermixing of the 2 fluids - lowering the flashpoint. They made it to within 10 ft of safety. When they flared the aircraft at about 10 feet over the runway - that's when the Left wing failed.

[Heliian]

I guess most people missed the extreme sarcasm in my last post.....

On the subject of Hydraulic fluids - 5606 and Skydrol are NOT interchangeable. They are completely different animals....however - if the smaller guys want a safer fluid all you have to do is switch to Mil-83282. It is completely identical and interchangeable with 5606. The only difference is 83282 has a much higher flashpoint.

5606 and 282 are not identical and not completely interchangeable. Please reference your aircraft manuals for the proper specification to be used.

[pelmet]

I guess most people missed the extreme sarcasm in my last post.....

I knew your statement about wearing Nomex was sarcasm meant to not be believed when in fact it was exactly what the T-28 pilot actually recommended and that is why I quoted that info. A lot of people may not read the actual article that have links so I made sure to quote it. Would have saved him a lot of grief(more than most of us could imagine).

On the subject of Hydraulic fluids - 5606 and Skydrol are NOT interchangeable. They are completely different animals....however - if the smaller guys want a safer fluid all you have to do is switch to Mil-83282. It is completely identical and interchangeable with 5606. The only difference is 83282 has a much higher flashpoint.

All brought to light here:
https://en.wikipedia.org/wiki/._Flight_420

You can search for the report if you like. The Wikipedia page is very simplistic and has errors....but you get the jist of it. There were many factors, part of the issue was the intermixing of the 2 fluids - lowering the flashpoint. They made it to within 10 ft of safety. When they flared the aircraft at about 10 feet over the runway - that's when the Left wing failed.

Sounds like extremely useful information....thanks.

[boeingboy]

5606 and 282 are not identical and not completely interchangeable. Please reference your aircraft manuals for the proper specification to be used.

Yes - Absolutely reference your manual. - but improved lubes, fluids and products are always coming out and can be used in place of older specs as long as they meet or exceed those specs. I was not clear when I said they were identical - I meant they were the same chemically and did not need component replacements. They are interchangeable.

Straight from shell
"Although the military did not move to phosphate ester type fluids they did identify the
need for a more fire resistant fluid as a direct replacement for MIL-H-5606. As a result a
synthetic hydrocarbon-based fluid, MIL-H-83282 was developed. This fluid is completely
compatible with MIL-H-5606 fluids and MIL-H-5606 hydraulic system materials. All physical
properties of MIL-H-83282 (now MIL-PRF-83282) were equivalent to or superior to those of
MIL-H-5606 (now MIL-PRF-5606) except for low temperature viscosity. In particular all fire
resistant properties of MIL-PRF-83282 are superior to those of MIL-PRF-5606."

[Capt. Underpants]

There were many factors, part of the issue was the intermixing of the 2 fluids - lowering the flashpoint. They made it to within 10 ft of safety. When they flared the aircraft at about 10 feet over the runway - that's when the Left wing failed.

IIRC, there was also a chance to shorten the flight time if they had chosen to land straight-in to the east instead of maneuvering to land west.