Hi - I'm writing POH for -8 and am looking for preferred technique or procedure for emergency descent. Is there consensus to handle most situations? Looking for an appropriate high speed/high drag technique in the -8 to quickly lose altitude in preparation for landing. So, say we have smoke in the cockpit and the engine is performing. Maybe our choices are a high speed descent, flaps down/airspeed at top of white arc or slipping with or without flaps. Which would be preferred? Thanks in advance.
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Emergency Descent
- Thread starter Drum
- Start date
Steep Bank.... PUSH
With a constant speed prop, prop full forward (high rpm) and throttle closed to idle / minimum manifold pressure. Pick your airspeed and rate of descent.
On my RV-6, it is a test flight maneuver for smooth air and NOT normal operation. The above power setting gives me 45 degree down angle, 180 KIAS (just under redline), and a 4,000 FPM descent rate. NOT something you want to do flying IMC.
On my RV-6, it is a test flight maneuver for smooth air and NOT normal operation. The above power setting gives me 45 degree down angle, 180 KIAS (just under redline), and a 4,000 FPM descent rate. NOT something you want to do flying IMC.
Dan 57
Well Known Member
I guess if flames are licking whatever cherished parts of one's body...
On the jets we reached 6K+ using max speed with speedbrakes, in IMC.
For sure, a CSP helps, the more so a 3 bladed... also wondering what the most effective technique for a fixed 2 bladed would be. A spin would sure loose altitude fast, but probably not the best of ideas either
Majorpayne317641
Well Known Member
You can control airspeed with G’s as you spiral down. That should get you down faster than full flaps.
There are some certified POH s like Diamond that says to speed up to try to put out an engine fire.
You would need to practice this since most people haven’t experienced pulling 4 1/2 plus G’s. If it’s a fire I want to get down as soon as possible without ripping the wings off but not caring if I damage the plane in the process. I want to survive.
There are some certified POH s like Diamond that says to speed up to try to put out an engine fire.
You would need to practice this since most people haven’t experienced pulling 4 1/2 plus G’s. If it’s a fire I want to get down as soon as possible without ripping the wings off but not caring if I damage the plane in the process. I want to survive.
I wouldnt “push”.. if you bank it steeply, allow the nose to cut through the horizon, you’ll actually be pulling the whole time. If you want to expedite the whole thing, roll a little past 90, it’ll drop the nose very quickly, no need to push.
Agreed! Idle, prop forward, spiral down at Vno if bumpy or expecting rough air, or VNE (TAS) if smooth air. Flaps and slipping isn’t going to get you down as quick.. but feel free to experiment and let us know!
Desert Rat
Well Known Member
Cessna has had this in the section 3 emergency checklists forever. For the good old 172 the Engine Fire in Flight checklist says it says pull the mixture and dive at 100 kts. If the fire doesn't go out, increase the dive until it goes out or you hit Vne.
I’ll have to try looking at my VSI.. 6000FPM? That’s impressi…. Almost hard be believe that you sustain 6000fpmjust with the falling leaf.
planenutz
Well Known Member
Aside from those with beta range on their props, the fastest descents I've ever seen carried out on a regular basis is by those dropping meatbombs (parachuting ops). The pilots at one airport I worked at would often have a bet with the meatbombs - last one to the bar buys the beers. The pilots rarely lost. After the jumpers are out the door the aircraft is rolled into a tight spiral descent at around 70-75 knots, flaps down with RPM and MAP maintained quite high to avoid shock cooling.
Of course you could always throw your machine into a spin. Wasn't that an old technique used to get down from above 8/8ths of cloud when you find yourself out of options? Stable, predictable, rapid loss of altitude. What could possibly go wrong?
Of course you could always throw your machine into a spin. Wasn't that an old technique used to get down from above 8/8ths of cloud when you find yourself out of options? Stable, predictable, rapid loss of altitude. What could possibly go wrong?
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larrynew
Well Known Member
In my RV-7A with a fixed pitch prop, I compared two methods for putting the plane on the ground ASAP. One was a tight 4+g spiral and the other mostly wings level nose down near VNE. Both at idle. The spiral was just a few seconds faster to lose 4K. But, it limited the landing options to directly below you and it was harder to pick a spot while in a tight spiral. I decided the nose down VNE method was worth a few seconds for a better chance of a survivable landing unless I was directly over a good landing option.
I did experience a burning plane a few years back. Though it was a turbo charged Cessna. In my case, faster descent did not do anything at all to put out the fire. I rolled and pushed. The ground was my friend. Though the gear failed, I flew it "all the way to the crash" as Bob Hoover suggested.
The two of us onboard walked (ran) away. The plane burned to the ground. It was upside down BTW after sliding a few hundred feet in rocky territory.
lndwarrior
Well Known Member
Not to be forgotten in this equation is that the ultimate goal is to "get on the ground", not how fast you can descend.
There has to be a sweet spot between descending as fast as possible while still being at a reasonable speed for landing off field (unless the fire just happens to be over the airport). Arriving at an aim point for landing at 200 mph is not going to be the quickest way to get on the ground.
There has to be a sweet spot between descending as fast as possible while still being at a reasonable speed for landing off field (unless the fire just happens to be over the airport). Arriving at an aim point for landing at 200 mph is not going to be the quickest way to get on the ground.
Nope, arriving at the proper place... at whatever speed works... be it 200 or slower is what counts. I do recall pulling the seatbelt so tight I could hardly breathe. The sound of the the prop tips grinding down is one I won't forget. I did expect it to stay upright though. I dug a trough, and slowed RAPIDLY. Which is a good way to bleed energy. The flip near the end of the slide was not expected. I got out and ran. (doors open on final) My 737 captain passenger hung upside down for a while... till he got his bearings. The fire was so intense the NTSB just gave up on probably cause. Not much to examine.
