747 Flight Deck escape reels.

[Hubbly]

Hi all

I have an extremely tecchy question, one which I have failed so far to get an answer to.

How long are the Inertia reels on the 747?

This is a two part Question:-
a) Length for a normal descent, i.e. out of the escape hatch and down the left side of the a/c.

b) Length for a right hand side descent i.e. out of the escape hatch over the dome and down the right hand side of the a/c.

This has been the subject of some serious debate, and would like to see if we can get some resolution on these questions.

Can anyone help?

[BelArgUSA]

For the 100/200 -
xxx
The escape reels are of sufficient length to be used through the escape hatch onto the LH side OR the RH side. There is very little difference in "length" passing the cable on either side. The hatch is offset (to the left) only by about 1 to 2 feet.
xxx
It is possible to use the same reels for exit through the RH upper deck door (and optional LH upper deck door) on the 100/200 type airplanes, or even through the spiral staircase (passenger 100/200 types) or ladder (cargo upper deck types) to be used for egress through L-1 OR R-1 doors.
xxx
In case of partial gear attitude (body gear NOT extended) it is possible that the length of the escape reel will not be sufficient to permit to reach the ground level, should the aircraft fall on the tail.
xxx
On the 300 series, escape reels are usable through the escape hatch only.
:)
Happy contrails

[Jumbo Jockey]

According to my manuals, on the 747-400 they are approximately 63ft (19.2m) long, and will allegedly reach the ground even if the aircraft tips on its tail. I assume this means down either side... Hope that helps.

[SMOC]

Don't use two reels thinking it will give redundancy, apparently it will double your descent speed! :{

[Hubbly]

Thank you kindly for the information.

It has been invaluable.:ok:

[BelArgUSA]

Hubbly - Forgot to mention.
xxx
On the 747-200C and 200F, there was an AFT CG limit for full upper deck occupancy.
If CG was AFT of (cannot recall the %), upper deck limited to "X" number of occupants.
Cockpit crew + additional people - based on number of escape reels.
This in case the airplane (body gear) would not extend, and fell on its tail.
Was also based on inflatable slides from upper deck + 1 or 2 upper deck doors.
These scary things they would make you jump from, and brake your neck...!
I looked in my AOM, but most of my notes for freighters have been removed.
With Cargolux, the 747-271C upper deck had some 16 F seats for passengers
xxx
:)
Happy contrails

[747dieseldude]

The CG limit is 26%.
In case the CG is behing 26%, plus no body-gear landing, the a/c might tip on it's tail so we are supposed to use L5 door with an escape rope fixed to it.

[fly123456]

Please excuse me for the thread dig up.

Don't use two reels thinking it will give redundancy, apparently it will double your descent speed!

Could somebody elaborate a little bit?

I've heard that story as well, but don't really understand how the inertia reels work.
Does it mean a 50kg man will fall down twice as fast than a 100kg man?

[Slasher]

Been a while since I've flown the Whale but I still recall that
lovable beast quite clearly -

Each reel provides the same ROD to the deck depending on one's
individual weight. So a 50kg nubile hostie should descend at the
same rate as the 110kg captain who was trying to chat her up.

If TWO reels were used by the same person, each reel would
perceive a lighter weight and allow an increase in inertial ROD.

This is why it was pointed out on Day One NEVER to grab a whole
fistful of reels, just because holding on to just one is outside one's
psychological comfort zone for a 40ft drop. Grab just one, hang on
and pray like hell it don't break! :uhoh:

18-Wheeler would be able to confirm this as I believe he's current
on type.

[grounded27]

Suppose some reel "play on words" expert advice could be given by the fight crew of hijacked PanAm flight 73. Got out before the terrorist's could reach the cockpit, rendering their plans useless.

[Bergerie1]

Slightly off the original question, but I tried the reel once on a 747-200 and it was a very comfortable controlled descent!

[18-Wheeler]

Slasher - I agree with all that - but I haven't been on 747's since late 2007 unfortunately, so things may have changed in the mean time.