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DC9 Tail Cone Evacuation  
User currently offlineBFS From United Kingdom, joined Nov 2001, 738 posts, RR: 2
Posted (10 years 1 week 9 hours ago) and read 5033 times:

Does anybody know if when the tail cone of a DC9 or equivalent is jettisoned for an evacuation, can it be attached or is the aircraft then effectively written off?


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User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 1, posted (10 years 1 week 9 hours ago) and read 4965 times:

It is reattached, or more likely the part is sent back to Boeing or written off and a new part fitted.

Many MD-81/82s with the original pointy tail have been retrofitted with the screwdriver tail. I think you'll find that if there is no damage/buckling/cracking of structural members, most airframe parts are not so expensive to replace as to require writing off the airframe.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offline4jaded From United States of America, joined Apr 2004, 248 posts, RR: 0
Reply 2, posted (10 years 1 week 7 hours ago) and read 4868 times:

It is my understanding that this part is designed to jettison from the aircraft in an evacuation. Like other emergency devises like slides there has been countless inadvertant deployments over the years. I am certain that when Douglas developed this aircraft and this feature they were aware of the
ooops factor. In most cases I am confident that it should only require an inspection before it is attatched back onto the airplane.


User currently offlineDalMd88 From United States of America, joined Jul 2000, 2534 posts, RR: 14
Reply 3, posted (10 years 6 days 21 hours ago) and read 4666 times:

The tail cone is a composite part that usually needs repair after a deployment. They are interchangable between airplanes so spares are not a problem. We take them off during the overhaul visit.

User currently offlineSafetyDude From United States of America, joined Sep 2001, 3795 posts, RR: 15
Reply 4, posted (10 years 6 days 15 hours ago) and read 4560 times:

Does anybody know if when the tail cone of a DC9 or equivalent is jettisoned for an evacuation, can it be attached or is the aircraft then effectively written off?
Almost everything on an aircraft can be replaced. For the tail cone on the DC-9, the plane would not really be a good buy if millions of dollars are lost when a hundred dollar item falls off.  Big grin

-Will



"She Flew For What We Stand For"
User currently offlineBroke From United States of America, joined Apr 2002, 1322 posts, RR: 3
Reply 5, posted (10 years 6 days 14 hours ago) and read 4508 times:

The tailcone on the DC-9 is mostly fabricated from fiberglass. When it comes off, either intentionally or inadvertently, it usually gets a ding (surfing term) at its pointy end which requires a minor repair before being reused.
I think the MD-80 boattail tailcone is also composite and would get dinged at the lower edge of the boattail when ejected.
The tail slide is mounted at the edge of the metal structure just forward of the where the tailcone comes off and it is deployed manually after the tailcone is out of the way.
There is a narrow catwalk, that gives a tricky access to the slide, with heavy canted curved beams that carry the empennage loads into the fuselage overhead. It is very easy to fram your head into one of these beams. Ouch, ouch, ouch!! The catwalk starts over the APU shroud and the compartment is usually very smelly from skydrol. Experience talking.


User currently offlineAa717driver From United States of America, joined Feb 2002, 1566 posts, RR: 13
Reply 6, posted (10 years 6 days 11 hours ago) and read 4422 times:

Broke--I thought "ding" was an aviation term. Smile

I was always leery when doing walkarounds on the -9/-80/717 after the instructor told me the tailcone weighs a couple hundred pounds! Talk about a ding!

Anyway, you never know when a mech or FA will be trying to deploy the aft stairs on a -80 and accidently jettison the tailcone. Insane TC



FL450, M.85
User currently offlineBroke From United States of America, joined Apr 2002, 1322 posts, RR: 3
Reply 7, posted (10 years 6 days 11 hours ago) and read 4379 times:

My first experience with someone dumping the tailcone when attempting to lower the ventral airstairs occurred on a DC-9-50 that we were modifying for introduction into Eastern's fleet. Someone inside the plane yelled out to lower the airstairs and my compatriot pulled the wrong handle!! He reached out without really looking at what he was reaching for. His first name was Henry and from then on, the external tailcone jettison handle was known by us as the "Hank" handle.

User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 8, posted (10 years 6 days 1 hour ago) and read 4207 times:

It's been said that the real reason for the screwdriver tailcone is so it won't roll so far when it is accidentally dumped.

I used to be able to claim that the only time in my whole career I ever had lost comm was in a DC-9 when the last bonding cable to the tailcone finally broke. We got in a high altitude stratus layer and the ice crystals brushing down the ungrounded tailcone caused a squeal in all the radios that did not go away until we left the clouds. Needless to say it took them a while to find the broken bonds in response to our writeup, but it fixed the problem.

I can't say it was the only time anymore because that happens to the Airbus every time it gets in heavy clouds at altitude.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineDL_Mech From United States of America, joined Feb 2000, 1926 posts, RR: 9
Reply 9, posted (10 years 5 days 15 hours ago) and read 4099 times:

The MD-90 has a different tailcone from the MD-80. There is a small nitrogen bottle installed inside the tailcone with an exhaust port that "blows" the tailcone to one side during deployment.


This plane is built to withstand anything... except a bad pilot.
User currently offlineMiamiair From , joined Dec 1969, posts, RR:
Reply 10, posted (10 years 5 days 15 hours ago) and read 4086 times:

First of all, the tailcone does not weigh a couple hundred pounds.

The DC-9 tailcones have an aluminized flame spray coating for the RF problem.

They are damaged more from hangar rash than operational use.


User currently offlineFBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7
Reply 11, posted (10 years 5 days 8 hours ago) and read 4024 times:

The original DC-9/MD-80 pointed tailcone weighs 48 kgs. It is designed so as to hit the ground and roll off to one side so as not to obstruct the tailcone slide when it inflates.
The "screwdriver" tailcone did not roll away as easily,and that may be the reason for the MD-90 having the mentioned gas bottle to deflect the cone away from the A/C:



"Luck and superstition wins all the time"!
User currently offlineMeister808 From United States of America, joined Jan 2000, 973 posts, RR: 1
Reply 12, posted (10 years 4 days 22 hours ago) and read 3976 times:

48 kg!!!

Damn that is light. I would have expected at least 500 lb.

-Meister



Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
User currently offlineFBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7
Reply 13, posted (10 years 4 days 20 hours ago) and read 3962 times:

That's right!
It should be able for just one person to handle it in case it doesn't clear the area by it's own after jettisoning.

Another interesting fact is that it remains in position due to air pressure/suction if the jettison handle is pulled during flight.It will fall off during landing,though.



"Luck and superstition wins all the time"!
User currently offlineDL_Mech From United States of America, joined Feb 2000, 1926 posts, RR: 9
Reply 14, posted (10 years 4 days 15 hours ago) and read 3938 times:

Another interesting fact is that it remains in position due to air pressure/suction if the jettison handle is pulled during flight.

I'll let you pull the handle............ Smile/happy/getting dizzy



This plane is built to withstand anything... except a bad pilot.
User currently offlineMD-90 From United States of America, joined Jan 2000, 8502 posts, RR: 12
Reply 15, posted (10 years 3 days 21 hours ago) and read 3880 times:

Due to the internal air pressure (at altitude, at least), I'll bet it would pop off like a cork from a champagne bottle.

It'd be interesting if someone tried a D.B. Cooper style escape from one and chose that method instead of trying to get out without having the rear airstairs beat them to death against the lower fuselage.


I would've guessed that the tailcone weighs about 100 pounds, so 48 kilos sounds about right.


User currently offlineFBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7
Reply 16, posted (10 years 3 days 18 hours ago) and read 3863 times:

Like a champagne bottle? Nope,the tailcone was not part of the pressurized area,the aft cabin door forms part of the aft pressure bulkhead.The cooling louvres on either side of the aft fuselage,just below the fin,creates a slight underpressure within the tailcone compartment and this keeps the cone in place even if the locking pins are pulled.It will fall off as the plane slows down after landing.


"Luck and superstition wins all the time"!
User currently offlineMD-90 From United States of America, joined Jan 2000, 8502 posts, RR: 12
Reply 17, posted (10 years 3 days 1 hour ago) and read 3821 times:

Interesting...

I guess you shouldn't open the door to get back there during flight anyway, since that would compromise the pressure vessel.


User currently offlineCanadianNorth From Canada, joined Aug 2002, 3389 posts, RR: 9
Reply 18, posted (9 years 12 months 4 days 22 hours ago) and read 3641 times:

If they were designed to come off when you pull the handles and someone pulled the handle on the ground, and someone happened to be standing under it, wouldn't that hurt come morning?



CanadianNorth



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