Engine fire in flight procedures - Skyhawk

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aaron1

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Aaron
Hello, I have a few questions regarding procedures for an engine fire in flight for a skyhawk. Step 4 in the POH states "master switch off." I'm assuming you're not supposed to turn it back on at any point afterwards to prevent reigniting the fire? So in other words, you can't send out a distress call or signal?

Secondly, if for some reason you had flaps in when the master switch was turned off, what is the best glide speed with flaps once the fire is extinguished? The emergency landing without engine power checklist states 65 KIAS, but I've always assumed that is for the approach to landing after the landing is assured. In other words, glide at 68 then when landing is assured, either pitch for 70 or 65 depending on flap setting.

Thank you for your help!
 
A fire in the air is deadly serious - if it is not contained it can consume the airplane very quickly. You're measuring your time in minutes and possibly not double digits.

The reason for turning the master off is that it kills the electrical system and if the fire is electrical in nature, it usually puts the fire out. Of course, we know that because the mags and maybe a fuel pump are mechanically linked to the crankshaft, then engine keeps running.

If I recall the emergency descent procedure, you want full flaps to create as much drag as possible. So, put in full flaps, turn the master off and start a 45 degree spiral down. You really don't want "best glide" here because the intention is to get on the ground fastest, not stay in the air longest.
 
If the fire is from the engine compartment, you want to be in a full slip..............so that the flames don't come straight back.
 
Ok my CFI taught me to just point the nose down, no spiraling. Was that incorrect? Btw I'm a low time student pilot so maybe the spiral was the next lesson.
 
Ok my CFI taught me to just point the nose down, no spiraling. Was that incorrect? Btw I'm a low time student pilot so maybe the spiral was the next lesson.
 
In the PA-24 I learned the 45 degree bank, Vne descent technique. The thought was that the air rushing past blows the fire out, I think I saw something in a POH (can't remember which) that said to keep the speed above 130 KIAS.
 
And here it is from a PA-28 checklist:

"Maintain an airspeed of at least 80 MPH IAS, and if altitude permits, proceed as follows"...Note the mention of __at least__
 
Tony R said:
Ok my CFI taught me to just point the nose down, no spiraling. Was that incorrect? Btw I'm a low time student pilot so maybe the spiral was the next lesson.
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I was taught the same as quoted below, but 45° banked turn (spiral). The airspeed was Vfe; the 45° bank was intended to dump more lift from the wings.

If you you think it is a fuel fire, mixture to idle cut-off and turn off the fuel.

bflynn said:
A fire in the air is deadly serious - if it is not contained it can consume the airplane very quickly. You're measuring your time in minutes and possibly not double digits.

The reason for turning the master off is that it kills the electrical system and if the fire is electrical in nature, it usually puts the fire out. Of course, we know that because the mags and maybe a fuel pump are mechanically linked to the crankshaft, then engine keeps running.

If I recall the emergency descent procedure, you want full flaps to create as much drag as possible. So, put in full flaps, turn the master off and start a 45 degree spiral down. You really don't want "best glide" here because the intention is to get on the ground fastest, not stay in the air longest.
Click to expand...
 
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50 years ago as a student pilot, I was taught to spiral down at 45 degrees pitch. Not something that has ever come up training since. At my flight review last week, the CFI's opinion was "point the thing down, stay just under Vne, and just get it on the ground". It was fun.
 
For a checkride anything in the published checklist must be followed.

For real life...

Where are you? Are you half a mile out on an ILS? Probably not a good time to slap the master off. :)

Is it dark out? Is there a runway nearby with pilot controlled lighting? Can you land without runway lights or a landing light? :)

Any hints as to the type and location of the fire? Have seen seized up alternator burn a belt before it broke and threw it and other alternator voltage regulator weirdness. Killing the alternator side of the master can make certain bad smells go away maybe. :)

As far as the descent goes, rolling at the beginning trades vertical component of lift for horizontal and it’s simple to maintain positive Gs and thus more drag during the entry. Roll with all your drag out and the nose will fall off and start down. Can also help you get down into flap speed if you’re in fast cruise in some aircraft.

Pushing from cruise might mean a bit of zero or negative G and takes longer to get going downhill in some aircraft. And you may have to dawdle to get into flap speed, if you care.

Again where are you and where do you want the airplane to be? Over mountainous terrain with a clearing “over there”? Better go over there. Nice field below? Spiral may be your choice as PIC today.

Are we attempting to change the O2 level and “blow the fire out” or just get the thing on the ground the quickest?

Some POHs have multiple techniques depending upon scenario.

You get to choose your own adventure in the real world, PIC. Even that slip thing someone else mentioned to keep the fire going out the other side of the cowl it needed.

Choose wisely. :) But choose getting it on the ground and getting the frack out of it. In flight fire eats airplanes.
 
Just don't be another Swissair Flt 111. They were on fire but didn't land because they were overweight. They started dumping fuel instead and lost it. (very germanic thinking!!!! "ganz rechts")


"""The fuel-laden plane was above maximum landing weight; as the flight crew dumped fuel as per procedure, they lost all control, and the doomed plane flew into the ocean uncommanded.""""

https://en.wikipedia.org/wiki/Swissair_Flight_111

We practiced the scenario in the Falcon 50 at FlightSafety, from FL410 one could get it on the ground (to a runway) stopped and evacuated in less than 5 minutes.
 
For small aircraft I greatly prefer (at least conceptually, since I fortunately have never had to do it for real) the power idle, full flaps, 45 deg bank, top of the white arc style of emergency descent. For one main reason: you are in the white arc with full flaps, so as soon as you roll out of the turn, the airplane will very quickly slow down to normal landing speed. You could roll out at a very low altitude and just put it down and get out quickly.

If you're doing the no-flaps, Vne method, now you get down to an altitude where you need to transition to land, but are still at Vne. Likely you have never practiced landing starting from Vne at, say 500 feet and have no idea how long it takes to slow down and land. Where do you aim?

However, a lot of this depends on the airplane. If you're in a post-1996 Cessna 172 or 182, for example, you're never really flying much above the white arc and can therefore put in flaps at almost any time. But if you're in something with a larger cruise speed-to-white arc gap, you may have to lose a lot of speed before doing this.
 
My CFI taught me to make a left turn spiral down as fast as safely possible to extinguish the fire and not have the prop funnel the smoke into the windshield.
 
This is a lot of great info! I knew it wouldn't be quite so simple and will always change depending on the situation, but I hadn't thought of many ideas mentioned here. It is most definitely an extremely urgent situation and a lot to manage in the moment.

The pilot must get down ASAP to keep from falling apart in the air, but also must find a place to land safely to keep from falling apart on landing. Just as important is the process by which they choose to descend. If there are no good landing spots beside or behind the plane, a forward slip may be needed. If it's better to land beside or behind, better to choose a 45 degree bank. They must keep smoke out of the cockpit (may need to slip during a bank if smoke is trailing into the cockpit). They should pre-set flaps before cutting power, will need to lose excess airspeed upon extinguishing the fire, not exceed Vfe/Vno/Vne, etc.

In the skyhawk with max 30 flaps, Vfe is 85 KIAS and up to 10 degree flaps, it's 110 KIAS. Emergency fire in flight checklist descent speed is 100 KIAS. Setting full flaps may or may not allow enough speed to extinguish the fire, but if you're close enough to the ground, you may just rather get down, get out, and run away.
 
Nobody yet says: Cut the fuel off at the firewall. My very first emergency was an in flight fire. I was a military flight student flying a turbine AC. Killing the master switch would have been the absolutely the worst thing. You need electric power to shut off the fuel valve. Called it in when I saw just a little smoke in the cockpit. Tower rolled the equipment and I landed next to the fire trucks. Killed the engine, then master off. Then, "Joe Kool" steps out, turns to the rear and could not see through the huge cloud of smoke. I bolted. But my helmet was still plugged in. It looked like an old silent movie gag when I went horizontal and landed on my back. The gathering crowd was visibly moved. Seconds later, yards away, I saw a 3 foot charred hole in the fuselage where the nicad battery used to be. Foam every where. You know that Foam was a slaughterhouse blood product in those days. Can't describe the stink when the sun hits it.

Years latter in commercial aviation, had a couple false alarms. The fire detection system used flame detectors. It seems that they detected fire by light and when they go bad, they are set off by simply flying on a westerly heading near sunset. A simple turn would have turned the light and horn off. Went off when I Shut the engine down.
 
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