Episode #231 "Turbulate the Air"

A place to post misc. feedback to individual eps.
Forum rules
We'd love to have you Reply to posts in this Forum, but please don't create new Topics here. One exception: If we haven't created a thread for a particular episode, feel free to get it started. For other subjects, I suggest creating new Topics in Virtual Hangar=>Other Topics. Thanks.
User avatar
Laminar
Posts: 171
Joined: Tue Dec 30, 2008 11:24 am
Location: 2B9

Episode #231 "Turbulate the Air"

Postby Laminar » Wed Apr 06, 2011 6:34 pm

I just had the eerie experience of listening to this episode while coming home to Vermont from my flying vacation in the southeast USA. It was eerie because the boys talked about all the places I had just visited the week before: Wallaby, Qwest, the Florida "ridge," Lookout Mountain, Sequatchie Valley. Everywhere except Lakeland, which I couldn't quite squeeze into the schedule.

Here's the Google Earth view of the hang glider ramp in the Sequatchie Valley. I flew by it several times in the glider. It's about 50 feet long and overlooks a 1700 foot drop to the valley floor. It looks very slippery from the air. I would be terrified to stand on it, I think.

-Rick

ramp.jpg
ramp.jpg (43.13 KiB) Viewed 2512 times

Biggles71
Posts: 53
Joined: Sun Jun 08, 2008 4:53 am

Re: Episode #231 "Turbulate the Air"

Postby Biggles71 » Mon Apr 11, 2011 5:02 pm

Another great episode guys....

On the Southwest Emergency descend; a full on emergency descend from 35000ft to 10000ft would take less than 5mins. One can expect a rate of descend of more than 5000ft/min. Not rare to see +6000ft/min.

Small correction on Dave's remark on deck angles; attitude with speed brakes deployed will be steeper than without,not less since the aircraft has more drag...

Also, negative G is not necessarily the case in an emergency descend, since the maneuver is supposed to be flown with the A/P On. Starting the descend is normally done while starting a turn because this makes the descend smoother and without negative G.

When structural damage is suspected, like in the southwest case, the emergency descend is/should not be flown at max speed. If it is done for a non structural damage like a pack failure, max speed is the way to go.

Hope it helps.
BTW, although briefly, it was great meeting you guys at Sun 'n Fun last week. A shame I had to run away before the end of your TUE podcast...

Bjorn alias Biggles
ga pilot & check airman A330 / A340
Flying was my first love and it will be my last one!

User avatar
ATC_Ben
Posts: 192
Joined: Mon Jun 28, 2010 6:31 am
Location: Melbourne, Australia

Re: Episode #231 "Turbulate the Air"

Postby ATC_Ben » Wed Apr 13, 2011 1:20 am

Biggles71 wrote:Also, negative G is not necessarily the case in an emergency descend, since the maneuver is supposed to be flown with the A/P On. Starting the descend is normally done while starting a turn because this makes the descend smoother and without negative G.


Although you want to get down rapidly there is no need to 'float' the cabin in doing so. Be brisk, but don't rush! So long as you are on O2 (number one action) and heading downhill at a good pace then I doubt the exposure for cabin crew or pax would be detrimental long term. Sure if they don't get onto a mask fairly rapidly they may pass out, but I don't think you'd have anyone dying or long term damage from not being on O2. The theory behind the autopilot doing the descent is that given the excessive descent rate that results the autopilot won't a.) Get distracted with the causal problem on the way down or b.) Pass out because of a crew O2 or mask problem and turn a depressurisation into a CFIT. If it's a slow leak then a rapid (rather than emergency) descent is probably more appropriate (it just depends on the rate of the leak) because you'll probably reach some intermediate altitude where the pressurisation system can 'keep up' with the leak.

When I used to work ramp on 737 freighters we had one bird that was notorious for needing rapid descents half way across from Perth because it 'leaked like a seive' it was constantly "finding" new holes in panels seams or door seals and the engineers patching it up and I don't think the packs were terribly great on that machine either... it was just the crummy one of the fleet. It could normally continue on at mid 200's flight levels to Melbourne, thankfully it's now found other skies to populate (or it may even have been parked in the US desert). I believe part of the issue was the main deck cargo door was cut in a little too far forward and thus the cans rubbed the door on the way in and out if you didn't take great care aligning them, wearing the main deck door seals at a great rate!
Caelus latus sursum


Return to “Episodes”

Who is online

Users browsing this forum: No registered users and 1 guest