Jet Engine Fire Protection Systems

A discussion of what fire protection systems are used for jet engine... as opposed to what is used in jet aircraft. There is definitely a difference.
As always, comments from professionals and amateurs are welcome.

heck these videos out:

[joshb]

Airline pilot here, apologies if these comments have already been said but wanted to offer 2 cents from this perspective.

The way most of us think about engine fires is there are places fire should be and places fire should not be inside of engines. If we get an engine fire warning on our panels, that is a clue that fire has *possibly* appeared where it should not be. Fire detection systems that I'm most familiar with are loop systems where if the loop is broken, we get a fire warning. This could be fire burning through the loop or a catastrophic failure with no fire that breaks the loop. The result is the same, a fire warning. We wouldn't know the cause in the flight deck and would treat both scenarios the same.

Generally, an engine fire falls under an emergency procedure, but I'd be hard pressed to find an airline pilot that has done this for more than a few years that gets worked up about an engine fire. In fact, if the engine is still making thrust and depending what phase of flight we're in, we may choose to delay fighting the fire because the thrust is more desirable.

When we hit our fire suppression buttons or twist the fire handles depending on the aircraft, several things happen:

1. One bottle of suppressant will deploy into the selected engine.

2. Fuel valves close that supply fuel to that engine. This will shut that engine down.

3. If equipped with a FADEC, the FADEC will likely order that engine / accessory gear box items to shutdown down.

Generally speaking, most aircraft I've flown are equipped with several separate firefighting systems. Usually 2 "bottles" of suppressant are available for the engine total. Meaning if you blow both on a left engine fire, you don't have any suppressant available if your right engine also catches fire. Why would be blow both? The emergency procedure will likely dictate to blow one and wait to see if the fire warning returns. If it returns, we'd blow the second bottle. Engine fires are exceptionally rare so it's a risk worth taking.

Cargo fire suppression is a separate system and this generally involves 1 quick acting suppressant and 1 long acting suppressant.

APU systems also generally have an independent suppression system.

Happy to answer any other questions as best I can.

Cheers

[bobqzzi]

I hope you are well. Thanks for posting

[prinzga]

I’ve lost track of your posts for a few years….then here you are. That’s a good thing.

[richardlincoln]

An update on the printed blade testing would be interesting if You can get security to allow that. Information about where the jet boat project has progressed to would be a interesting subject as well.
Thank You for the time and effort You spend on Your channel Agent Zed. Best Wishes to You, Your Family and Friends.

[sam]

Soon to be A&P here, working in commercial maintenance. The separation between aircraft mechanics and engine mechanics/overhaulers is definitely still a phenomenon. A&Ps have the legal authority to do both but you really kinda choose a path in practice.

[LaTeamPrep]

I've seen an APU fire detection system! Based on some resistive lines with a sum of a certain ohm value. So if there would be any fire where it is placed, the value would change due to a rupture in the sensor line, therefore triggering any extinguishing protocol in place!!! Really amazing thing.

[pedroferreira]

I went and watched a video you mentioned, YAP! It's toasted!

[gregebert]

In summary, it sounds like "engine fires" that are caused by an actual defect within the engine itself are probably rare.

BTW, Whistlin Diesel has another crazy video with his jet engine mounted on a merry-go-round....

[rollamichael]

I got more informed watching your vid (as I always do). Love the conclusion!

[laudennn]

very cool info. always learn something. thank you!!

[DougBow]

As always, an excellent explanation. Thank you for your efforts to share your knowledge. 😊

[robpeters]

What’s sup Agent Z!
Fellow Canuck here. I was wondering how those jet cars, bus and truck makes those gigantic smoke and flame throwing events before they fly down the track?
How do they anchor it to the vehicle?
As always, I love your channel!
Always informative and on point!

[mynamedoesntmatter]

It’s usually halon with the mindset of “it’ll put out fuel and oil fires and if it’s metal… welp… good luck.”

As for airframe side, most planes’ fire bottle arming button (the big red button) closes a combination (or all) of: bleed air, fuel, electrical power, and hydraulic to isolate any and all sources of fuel out of the fire area. The bottle button is usually next to the big red shutoff button.

Usually a fire happens from loose or broken lines in the accessory area that ignite some combustable material or an accessory fails spectacularly. Usually an engine internal fire only happens during startup because there’s simply too much air blowing by at any stage after idle.

[stuartcollett]

Very entertaining video.

Not sure if engine fire inside the engine or engine fire detected by the fire wire outside the engine is much of a different checklist. Certainly what I used to fly it was encompassed in one engine fire checklist.

[fuzzydk]

8:50 google says a PT6 ignitor is a few joules per spark, that's only 50-100 times a car ignition

[NiHaoMike]

The Qantas Flight 32 near disaster was caused by an undetectable internal fire due to an oil leak. The most surprising part is that the manufacturing defect that caused the oil leak was clearly visible and just accepted.

[michellepowell]

Usually Halon or similar. two bottle. one quick discharge, one slow discharge for prolonged protection.

[stephanhiltenkamp]

On your red chicklets... I think the rocket engine people call that Situation "engine-rich exhaust". Accurate and hilarious

[RC-Dorigas]

What is the pourpose of the "pipe" over the Spey engine? 30:38
I attended a local airshow recently ad saw a similar tube coming out from the bottom fuselage on an L-39, is that a discharge port of some sort?
How does it operate and in what circumstances?
Thanks !

[zapfanzapfan]

Driving a jet engine powered Kei truck on the free way... wow... wonder if DMV approved of that? 🙂

I thought it was gonna be someone doing jet truck shows on airshows where spitting flames is the point. I don't think he is concerned with engine life considering the indoor helicopter accident and the jet engine flying off the merry go round...