avroarrow
Posts: 804
Joined: Wed Sep 19, 2001 10:40 am

Would This Warrant An Emergency Descent?

Tue Apr 19, 2005 7:42 pm

Saw this new photo in the DB today.

View Large View Medium
Click here for bigger photo!

Photo © Robert Thomas


I know he says its only the outer pane, but to stay at FL450 as he mentions in his caption seems odd to me. Wouldn't you want to descend to a lower altitude (FL100?) to reduce the pressurization load on the windscreen in case the main layer of the windshield was damaged? Or maybe I'm just ignorant?
Give me a mile of road and I can take you a mile. Give me a mile of runway and I can show you the world.
 
Contact_tower
Posts: 534
Joined: Mon Sep 17, 2001 4:05 am

RE: Would This Warrant An Emergency Descent?

Tue Apr 19, 2005 8:27 pm

If they where, let's say mid atlantic, FL100 would but a real dent in the range of the plane. Perhaps even make it impossible to make it to airport?

I've experienced controlling am 737 that got a cracked window, and they continued to destination, at filed cruiseing level.
 
corey07850
Posts: 2335
Joined: Wed Feb 04, 2004 4:33 am

RE: Would This Warrant An Emergency Descent?

Tue Apr 19, 2005 8:31 pm

I think his comment meant the pane cracked at FL450, not that they are still at that altitude, but I could be wrong
 
242
Posts: 495
Joined: Tue Oct 24, 2000 1:10 pm

RE: Would This Warrant An Emergency Descent?

Tue Apr 19, 2005 8:36 pm

It's the outer layer. Not really a big deal-- but may require a ferry flight to get the aircraft to a maintenance station.

It's a windshield heat problem, and it happens more often than you think.
 
lowrider
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Would This Warrant An Emergency Descent?

Tue Apr 19, 2005 10:26 pm

Depends, if it is only the outer layer, then the checklist may not require a descent. If I recall, speed is as much a limiting factor as pressure.
Proud OOTSK member
 
User avatar
HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Would This Warrant An Emergency Descent?

Tue Apr 19, 2005 10:38 pm

Not Sure what Alt he is when the Pic was taken.
But the Inner pane is capable of withstanding the pressure loads.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
wing
Posts: 1357
Joined: Sun Oct 01, 2000 9:10 pm

RE: Would This Warrant An Emergency Descent?

Tue Apr 19, 2005 10:45 pm

What I understand from the caption that he says the window cracked at FL 450,he doesnt mention flying the rest of the flight at FL450.

I can not comment without seeing the QRH of the Gulfstream III on this incident,still I am sure they handled it according to the requirements and limitations of their aircraft

My A-321 QRH limits the max FL at 230 in a cracked window situation.

Don't mix the total cabin pressure loss with this situation since you still can control the pressurization on a crack windshield problem.An emergency descent to 10000 feet or highest alt on the route is required only when you cant control the cabin pressurisation anymore.
follow me on my facebook page" captain wing's journey log"
 
greasespot
Posts: 2955
Joined: Sat Apr 24, 2004 10:48 am

RE: Would This Warrant An Emergency Descent?

Wed Apr 20, 2005 1:57 am

No the maintenance manual pretty much says no restrictions unless the captains vision is obscured. It leaves it vague so different captains do different things. I have seen freighter come home from out station with windows like that after they cracked on descent to the station. Since there was no maintenance nd the pilots wanted to come home they flew home.

When you lose window heat i( usually what caused the cracking like that)t is a speed restriction due to less impat resistance as opposed to a pressuruzation problem.

The outer payne has nothing to do with pressurization. It is the heated layer for impact resistance.

You can continue to fly at altitude with out any problems.

At least that is the B727 and B737.

GS
Sometimes all you can do is look them in the eye and ask " how much did your mom drink when she was pregnant with you?"
 
amtrosie
Posts: 273
Joined: Thu Jan 06, 2005 6:44 am

RE: Would This Warrant An Emergency Descent?

Wed Apr 20, 2005 8:44 am

Per the emergency procedure for the GII: (virtually identical to III)
1. Reduce cabin pressure diff. to 6.0psi max.
2. Windshield heat switch-off.
3. Pull associated C/B's (it lists them, power and control)
4. Windshield heat switch-ON
5.Maintain current airspeed/mach or slower for remainder of flight.
BELOW 10,000 ft.
6. Airspeed max 235 KIAS
7. Max climb/descent 2000FPM
8. avoid all icing conditions.
It does caution the cockpit crew to do smoke goggles as a precaution.
 
avroarrow
Posts: 804
Joined: Wed Sep 19, 2001 10:40 am

RE: Would This Warrant An Emergency Descent?

Wed Apr 20, 2005 10:06 am

Thanks for the input guys. I was unsure how much of an effect the crack on the outer layer would have. I guess the consensus is that it probably had minimal to no real effect. But it sure does look rather impressive.  Smile
Give me a mile of road and I can take you a mile. Give me a mile of runway and I can show you the world.
 
troubleshooter
Posts: 420
Joined: Mon Feb 07, 2005 5:22 am

RE: Would This Warrant An Emergency Descent?

Wed Apr 20, 2005 12:05 pm

I have witnessed such a windshield failure once during a flight on a C-160 "Transall" (German Air Force). First there were some sparks visible on one part of the heated windshield area. The captain switched the heating off, the sparkes stopped. We could see a small area of delamination (one small bubble). Then he switched the window heating on again. The sparks were visible again and then there was a loud "bang". The windshield looked similar to the one one this picture of the Gulfstream. They reduced airspeed and flight level (no emergency descent) and we returned to our airbase.

View Large View Medium
Click here for bigger photo!

Photo © Stefan Welsch

This job sucks!!! I love this job!!!

Who is online

Users browsing this forum: thepinkmachine, zaphod42 and 18 guests