For Concorde Drivers

[pegleg]

Are there any procedures in force regarding decompression on Concorde in terms of pax oxy masks etc. Or is there no point given the speed at which blackout would occur at normal cruise altitudes.
Also are one/all flight deck crew required to be on oxygen at all times above a certain level.

[WOK]

All procedures/equipment relating to O2 are the same as any other L/haul operation, except that the flt crew O2 masks are of the pressure-breathing type.

[Dave Incognito]

I was told be a somewhat mad engineering lecturer that at Concorde cruising levels, a depressurisation will drop the cabin pressure to the point where water will boil at body temperature. (i.e. you will start to boil)

He then went on to assure us that the O2 gear was therefore useless at this altitude.

Is there any truth to this?

Thanks in advance, Dave.

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Flying is easy - just throw yourself at the ground and miss.

[twistedenginestarter]

I'm a bit sceptical about this.

Whilst we're made of water so is a jelly. You wouldn't expect it to boil if you put it in a vacuum.

Certainly you'd lose moisture more rapidly at 50000 feet but I would have thought you'd have more of a problem with eg CO2 loss.

The effectiveness of pure oxygen would also be rather limited if not pressurized. Generally however I would guess it's much the same as at 40000 feet only worse but not as much worse as the difference between 20000 feet and 40000 feet.

[BN2A]

Although your blood would boil if the pressure outside was low enough, you would have to go higher than Concorde cruises (not cruisED, cruisES - come on CAA...).
Can't remember the exact altitude, despite passing HP&L the other week... :rolleyes:

As for time, you can be sure that if the worst were to happen, Concorde descending at Mach 2 wouldn't take long to get down!! http://www.pprune.org/ubb/NonCGI/eek.gif

[RW-1]

Well, the books I have say the low pressure that would bring the boiling point down to 98 degrees is around 61,000 feet.

Am I incorrect in that the concorde cruised (and hopefully will again) at 65,000 ?

Even if so, while your bodily fluids would indeed begin to boil, rising in temp to that point. There are a number of things that have to factor into this.

How rapid a depress are you talking about?

As I understand it, concorde has smaller pax windows to begin with, if one blew, it would take "an amount" of time for the pressure to drop, and figuring as BN2A states, as soon as Depres occurred, the crew would likely begin a dive (doesn't have to be steep, as soon as you go lower the "boiling point" would rise above body temp, and each successive second even higher).

As for O2 being useless, it is a reference to what WOK told you. at those high altitudes, there isn't enough atmospheric pressure for you to take a breth, therefore the oxy system is a pressure fed type. Very uncomfortable to use and you get tired after just a few minutes. In this system, o2 is pressure fed into you and you then have to forcefully exhale, like blowing out a candle. when you relax again, your lungs get filled up, kinda like placing your mouth on a running hose of water. You could see how that could wear you out :)

Twisted, wouldn't know about the vacuum, however the high alt and boiling point is valid and has been demonstrated in hyperbaric chambers in the military for the last 40 years or so.

A rapid decompression is performed with students in one chamber at 10K, and the main chamber raised to 70K, then a flow valve is undone between the two and you can watch the jar boil, while safe in your pressure suit.

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Marc

[This message has been edited by RW-1 (edited 21 February 2001).]

[twistedenginestarter]

I accept blood would boil, but not while it's still inside you. If you insist on taking a bottle of the stuff with you, that's your business.

Concorde cruises at 50000 feet rising slowly to 60000 feet.

[SFly]

Concorde climbs to a normal initial altitude that most heavies operate at and immediately begins a slow rise (aided by fuel and therefore weight loss) to the peak of it's Mach II cruise, generally about 60,000 feet. Upon reaching peak altitude, the aircraft slowly begins descending back down to it's original intial altitude where the pilots will either wait to descend for landing or begin the descent immediately. So even if there was depressurization in flight, chances are very slim that it would happen at that particular point in time. If it did, you're right -- a Mach II descent wouldn't take long at all. I shouldn't think the size of the windows would be a factor really -- the windows are still big enough to let a depressuriztion happen in less than 10 seconds, in order to be a factor it would have to be puncture-hole size.

So the answer to the boiling question is: "virtually impossible". Also, I don't belive the captains are required to wear oxygen for any length of time during flight bar any kind of emergency.

Hope this helps.
SFly :) :)

[WOK]

I say again: Conc SOPs are the same as other LH aircraft.

The profile flown is reheated climb/accel to approx 43500' (M1.7), then unreheated climb/accel to 50000' (M2.0) then cruise climb at M2.0. Max alt LHR-JFK 57000'-59000'. Max crz alt = 60000', achieved at light weights or LHR-BGI. This crz/clb continues 'til descent required, then speed reduced to approx M1.5, descent and decel started. M1.0 achieved at 40000ish.

As far as windows and depressurisation go - with all air supplies running the cabin alt will not go above 15000' with TWO pax windows out. The chances of the cabin alt rising above 40000' are therefore very slim.

Emergency descent, as previously stated, is fairly rapid.

'nuff said?

PS during recurrent SEP training flt crew need to demonstrate their ability to don 02 mask in less than 5secs and communicate while pressure breathing. Not as horrible as it sounds, but not too comfortable, either.

[Bellerophon]

Concorde climbs at VMO, until reaching M2.0, at around FL500, and although I haven’t seen any other heavies operating up there yet, I would love to see XH558, the Bruntingthorpe Vulcan up there with us one day! :) :)

Once at M2.0, she slowly cruise climbs, with a maximum authorized altitude of FL600, and, like any other aircraft, Concorde stays at her most efficient altitude until top of descent, with an extra factor in the descent planning being the need to be subsonic 35 miles before any landfall.

All the O2 procedures are normal for long haul passenger aircraft operations, with the flight crew having a pressure breathing system, for reasons already posted. The crew does not routinely wear O2 masks at any stage during the flight.

The passenger windows fitted in the production aircraft are smaller than the passenger windows in the prototype aircraft, a change made during certification and test flying to ensure that the aircraft met all the relevant decompression standards.

One advantage of Concorde is that with a normal cabin differential pressure of 10.7 psi, the cabin altitude is a lot lower at any given aircraft altitude than on conventional subsonic jet aircraft.

Rest assured that if we had to, we could get you down from FL600 very quickly!

[muhdzailan]

Concordes fly at a speed of mach 2 and will a blackout occur at that speed?I have never flown on a Concorde and I want to have an experience being on board the concorde.If anybody has been on the Concorde,please tell me your experiences.

[This message has been edited by muhdzailan (edited 26 February 2001).]

[pegleg]

Many thanks to all for the informed answers. All is very clear now.