747 question
 

i'm curious, can a 747 land safely with no power? eg fuel exhaustion. does it need an extremely long runway?

Did it in a sim a few months ago.

Flew like a brick.

We made a turn too low to correct on final, and crashed. No time to set up and try again.

I would think doable though

Yes, but a lot of luck required.

As ph has just said, the slot at idle with flap is quite steep. Not quite Space Shuttle, but up there. The other hassle is that the B747 is really "fly-by-fluid". 160kts as a minimum to keep the hydraulic pumps working to provide enough pressure to keep the flight controls operating.

Having said that, if you're high enough, you can take flap and gear but they are S - L - O - W to operate. You have to allow each selection to take full effect then select the next. LE devices have their own issue in this and add to the flavour.

Very much a case of "don't try this at home!!" :uhoh:

G'day ;)

Consider

(a) a throttles closed descent is very low thrust.

(b) all engines failed is a bit lower thrust ... bit higher ROD

(c) the rest of the aircraft's aerodynamics etc., probably doesn't know that all the engines have failed

(d) end result is a forced landing with higher keypoints and the pilot needs to be very attentive to energy management

We used to give students the typical 10,000ft somewhere near the airfield second failure on the 737-200/300/400 and there was no problem getting it on the runway in a tidy fashion.

What I found to be particularly interesting was that a wide range of techniques all worked fine .. provided that the pilot was attentive to the energy situation and stayed well ahead of the aircraft.

A significant number of folk didn't succeed the first or second time while they got their acts together ... however, once the problems had been identified it really wasn't any different to doing a forced landing in a C172 (except for the wheels thing).

Should be similar for other FAR 25 aircraft.

Did it in a sim
 

Did it in a sim, but with APU running, so hydraulics and electrical power were available.
The 742 glides down a 4 degree slope, so it is easy to calculate the glide path and reach your runway. My impression is that the 74 is quite a good glider.
Since in my case I had gear and flaps, I used the 2-engine profile, landing with 25 flaps, so most runways will suffice.
If you are out of fuel, then flapless landing is in order, and without any brakes (that is if you are foolish enough to get the gear down), that would mean a parking spot on the grass.

Best of luck

did anyone see the Horizon air crash TV prog last night. they showed footage of a plane landing with one engine out, (the pilot announced "this is going to be a hard landing") it basically crashed into a ball of flames. was that just down to pilot error? or are some airliners harder to land with engine failures than others?

In a glider you need some means of controlling lift/drag to adjust your glide slope. You can't use elevator as that effects your speed too much. What could you use engines out in a heavy?

It sounds like you might be referring to the Sioux City accident. If so, there was a lot more wrong that just an engine failure (viz., no hydraulics, no flight controls: deep deep deep trouble). They only managed to "steer" using differential engine thrust. It is amazing that the crew got anywhere near an airport, let alone live to tell the tale.

If you still have rudder authority then sideslip?

In my Hang-gliding days we altered the approach pattern, either by use of a curved final/base leg or 's' turns on final.

Don't fancy that in a 747 glider mind.:uhoh:


And, yes I did get it wrong, lots of times.:ouch:

Avianca tried it in a 707 near JFK. Didn't turn out so well.

The Horizon D8 crash was caused by a high pressure fuel line letting go in the engine compartment. Which caused the engine to fail, when the pilot lowered the gear the resulting explosion took out both hydralic systems. When they touched down, they had no brakes or streeing. At that point the best you can do is to hold on.

Your comment may well have been meant to be TIC ..... but there is a heck of a difference between planning an (all) engine(s) out appproach and being put in an unplanned situation with all the drag out already and at a range of 10?nm on the glideslope when you loose the engines.

Suggest you ignore the Avianca comparison in what is a theoretical discussion.

I think an Evergreen crew tried that ovel LHR a few months ago. Although they had partial power available.

Oh,top bunk. The Q is answered. Can we not have some fun?

If joking about people losing their lives is your bag .... I pity you:yuk:

Apparently not, if you are around. Good luck.