Any 777 pilots here? Can the cabin pressure be shut off at the cockpit?

[c1steve]

The plane went to 45,000 feet early on. Could the pilots kill the passengers by depressurizing the plane. Could someone on the ground have smuggled in oxygen tanks for the pilots.

The plane's movement were so deliberate, I suspect they may have killed the passengers early to control the plane, then taken it to a desert area for future use such as a suicide mission to Jerusalem.

What can the cockpit crew turn off? One of the plane's position transponders was apparently not working before the plane left the ground. I am not a conspiracy theorist, but this situation appears to me to be well planned.

-Steve

 

[BoilerUP]

Not a 777 pilot, but yes you can turn off the packs and bleed air (pressurization). Unless the cabin is 'dumped', the outflow valves will drive closed and attempt to keep the cabin around 14500-15000' and masks will fall somewhere around 10,000' or 14,000' (not sure about Boeings). I do believe pax mask auto deployment can be turned off from the cockpit, but if you force open one of the doors with a paper clip or pen and pull on the mask you would be able to get O2 from the oxygen generator (though that flimsy little mask won't do much at high altitudes).

The bigger question really should be "can a 777 climb to FL450?"

And the answer would be NO, not at the weights they likely were at during that point in the flight...not without a zoom climb that's going to stress the HELL out of that airplane. And once you get there, you're not gonna stay there very long as you've bled off so much energy that you'll stall if you don't descend. Then again, at FL450 time of useful consciousness is something like 5-7 seconds. Also, crew(pilot) oxygen masks are not rated for continuous use above FL410, so if the cabin was depressurized and a pilot wearing a mask did climb that high, it is entirely probable that they suffered hypoxia if not unconsciousness as well.

As somebody that flies at FL450 on a VERY regular basis, I'm kinda dubious of radar height reports unless it was a modern AEGIS-style air defense radar.

 

[427Cobra]

I fix Boeings for the worlds most profitable Airline, for the most part the systems and logic behind the systems is the same across the current generation of Boeing products, the pressurization and passenger O2 can be turned off in the Flight Deck, the pressurization system has two primary but separate control systems which switch sides each flight, they are completely automatic, the pilot selects his final cruise FL and it does the rest, should both of those systems fail, the outflow valve can be controlled manually by either AC or DC power, the passenger O2 system is completely separate from the Flight Deck O2 system, the pilots have there own O2 bottle, O2 masks with built in microphones, in the passenger compartment each row of seats or bank of seats has a PSU(passenger service unit) the FA call button is there, gasper fan outlets and reading lights, as well as O2 masks for each person in a seat plus an additional for a baby or FA if need be, in the PSU is a O2 generator to supply forced O2 to each user, by pulling the mask when deployed out of the PSU pulls a pin, a plunger pierces the containers inside the O2 generator and the two chemicals mix and make O2, each Lav and the FA stations are all equipts the same as the PSUs, when the passenger O2 system in on, the deployment of the passenger masks is automatic, in the cockpit a cabin altitude warning horn will sound, telling the bus drivers to don there masks and get the plane down to a safe altitude. I would like to point out there is no access to the cockpit on modern airliners in flight from the passenger compartment, lets just say the door has been modified and leave it at that, and can only be opened from the inside, and since 9-11 crews know openning the door is certain death for them and everyone else. During a depressurization event with no forced O2 will deny each person the ability to open his/her diaphram to allow them to breath, accending to FL45(if that really happened) is not required to kill everyone. Transponders do not have an On\Off switch, but each has a circuit breaker in the cock house.

Here is my Therory, planes that do not operate in US Canada or European airspace are NOT maintained or operated at the same level as planes that are flown in our airspace, for instance a broken transponder is not dispatchable on a ETOPS flight, in Asia or Africa......................, a series of unfortinate events lead to this planes demise, the loss of the cabin(pressurization) caught the crew off gaurd, Oto flew the plane until the fuel tanks ran dry and the bird lawn darted into the water, if this was a hijacking there would only be hours to get back into the air and strike its target, every satilite we have has already searched every possible landing strip for this plane, only large airports will have a hangar big enough to hide a 777, all souls are on the bottom of the sea waiting for us to find them, the FDR\CVR pingers(if maintained) only have about 20 days left before they stop saying here I am come get me.

 

[sharac]

since 9-11 crews know openning the door is certain death for them

I think BJ overrides that knowing in huge % of flights.

 

[Maggot]

I fix Boeings for the worlds most profitable Airline, for the most part the systems and logic behind the systems is the same across the current generation of Boeing products, the pressurization and passenger O2 can be turned off in the Flight Deck, the pressurization system has two primary but separate control systems which switch sides each flight, they are completely automatic, the pilot selects his final cruise FL and it does the rest, should both of those systems fail, the outflow valve can be controlled manually by either AC or DC power, the passenger O2 system is completely separate from the Flight Deck O2 system, the pilots have there own O2 bottle, O2 masks with built in microphones, in the passenger compartment each row of seats or bank of seats has a PSU(passenger service unit) the FA call button is there, gasper fan outlets and reading lights, as well as O2 masks for each person in a seat plus an additional for a baby or FA if need be, in the PSU is a O2 generator to supply forced O2 to each user, by pulling the mask when deployed out of the PSU pulls a pin, a plunger pierces the containers inside the O2 generator and the two chemicals mix and make O2, each Lav and the FA stations are all equipts the same as the PSUs, when the passenger O2 system in on, the deployment of the passenger masks is automatic, in the cockpit a cabin altitude warning horn will sound, telling the bus drivers to don there masks and get the plane down to a safe altitude. I would like to point out there is no access to the cockpit on modern airliners in flight from the passenger compartment, lets just say the door has been modified and leave it at that, and can only be opened from the inside, and since 9-11 crews know openning the door is certain death for them and everyone else. During a depressurization event with no forced O2 will deny each person the ability to open his/her diaphram to allow them to breath, accending to FL45(if that really happened) is not required to kill everyone. Transponders do not have an On\Off switch, but each has a circuit breaker in the cock house.

Here is my Therory, planes that do not operate in US Canada or European airspace are NOT maintained or operated at the same level as planes that are flown in our airspace, for instance a broken transponder is not dispatchable on a ETOPS flight, in Asia or Africa......................, a series of unfortinate events lead to this planes demise, the loss of the cabin(pressurization) caught the crew off gaurd, Oto flew the plane until the fuel tanks ran dry and the bird lawn darted into the water, if this was a hijacking there would only be hours to get back into the air and strike its target, every satilite we have has already searched every possible landing strip for this plane, only large airports will have a hangar big enough to hide a 777, all souls are on the bottom of the sea waiting for us to find them, the FDR\CVR pingers(if maintained) only have about 20 days left before they stop saying here I am come get me.

My dad flew for the now defunct TWA. I grew up on Martin 404's and DC3's. Just curious...what IS the worlds most profitable airline?

 

[sharac]

Usaf

 

[KYpatriot]

Usaf

LOL.

"They must keep that money, cause I ain't seen a nickel of that million dollars..."

 

[sharac]

 

[aqualung]

I only have 2500 hours on the 777, so don't call me an expert, but I don't see any posts from genuine 777 pilots here.

Just exactly how are you going to turn off the pressurisation?

OK, so you do that, but when the cabin altitude hits 14,000ft, those masks are coming down. That's NOT something you can override from the flight deck. It's automatic for a reason...

Oh, and I think, without going into my FCOM1 (Limitations), that the max operating altitude of the B777 is 44100ft. So NO, the 777 aint going to 45,000ft.

Out of KL (Sea level) on something like a 7-hour flight, we're talking less than half fuel load (not even close to the WAT limit), I doubt even the wings would be full, so typical cruise altitude will be F390, maybe F410. Most likely, F370-F390.
Remember, the flight was proceeding NORMALLY, until handover to Ho Chi Minh control...

As a hijacker, from there on, you're hoping that you can out-last the passengers and crew, before they come hammering on that flight deck door. Oh, yes, they're trained to do that these days, just in case...

It really is a baffler!

N

 

[aqualung]

I fix Boeings for the worlds most profitable Airline,

Transponders do not have an On\Off switch, but each has a circuit breaker in the cock house.

Fix is a relative term....... A deferred defect entry into the ATM is NOT fixing the problem....

Typical engineer's attitude.

Oh, and Dude, the transponder DOES have an off switch.

Patently, you're not an avionics guy.

N

 

[BoilerUP]

I only have 2500 hours on the 777, so don't call me an expert, but I don't see any posts from genuine 777 pilots here.

Just exactly how are you going to turn off the pressurization?

Turn off the packs and bleeds?

OK, so you do that, but when the cabin altitude hits 14,000ft, those masks are coming down. That's NOT something you can override from the flight deck. It's automatic for a reason...

You can't disable the auto drop in the cockpit on the triple?

I know you can do that on puny Citations, and I seem to recall that ability on the CRJ and also on the 737 and 756 but its been a while since I've been in the cockpit of an airliner.

Oh, and I think, without going into my FCOM1 (Limitations), that the max operating altitude of the B777 is 44100ft. So NO, the 777 aint going to 45,000ft.

You can certainly zoom it up there...if it'll fly up there is another question entirely, likely answered by the stick shaker and pusher.

 

[flounderv2]

My dad flew for the now defunct TWA. I grew up on Martin 404's and DC3's. Just curious...what IS the worlds most profitable airline?

About the only profitable airline is Southwest from my understanding.

 

[aqualung]

Man,
Both hockey sticks will have passed each other at F450!!

Bear in mind I haven't flown the BLT in 12 years or so, but, we have a switch to DROP the o2 masks, but not a switch to STOP them from coming down. STOPPING 350 pax from breathing?? That's counter intuitive!

I'd have to look at FCOM2 to be certain, but I don't recall any mechanism to turn the o2 off before the masks deploy. But the spanner twirler is right about one thing, the FLIGHT crew have a separate source of o2.

The comment about F450 was addressing an earlier post. The B777 does NOT fly at F450, and everything about this flight was normal until it reached the edge of Malaysian airspace. It got freaky AFTER that.

And in case you're wondering, BLT = Big Light Twin

N

 

[c1steve]

Thanks for all the detailed replies. If you were a pilot and terrorist wanna-be, would you and copilot be able to take the plane somewhere to a hidden location? If radar could have been evaded, I can see landing on the desert and covering the plane with camo netting.

The passengers could be disabled or not.

The old Bond movie, Thunderball, had such a plot. Some terrorists think big, and I would be surprised that this was some sort of pilot's suicide, as everything seems so well thought out.

 

[427Cobra]

Fix is a relative term....... A deferred defect entry into the ATM is NOT fixing the problem....

Typical engineer's attitude.

Oh, and Dude, the transponder DOES have an off switch.

Patently, you're not an avionics guy.

N

I'm not an Engineer, I can't afford a pay cut, and I'm not a hardcore Avionics guy either, so the Transponder does have a off switch, the passenger o2 does too, it's just a circuit breaker, I like getting dirty, engines, gears, doors, flight controls, hydraulics, no MEL stickers on birds leaving the hangar, so keep over temping the engines, exceeding flap speeds, flying through lightning storms, or don't do any of those, I still get paid, I'm required insurance, and I have the seniority to be on days with weekends off.

 

[Regular Guy]

Easy boys, no need for personal attacks if you disagree with someone.

Will the triple make it to 450 - most likely it will depending on weight. Yes, that is above it's certified service ceiling. There are additional requirements for certification for flight above certain altitudes, so the certified service ceiling is not necessarily directly related to altitude capability. If the weight is low enough, there is plenty of room between Vmo and Vmin for flight at higher altitudes.

Yes, the transponder can be turned off via a switch on the panel. It also turns off the ADS-B.

O2 masks are a moot point. The chemical generators in the masks that fall from the ceiling only last 15 minutes and are not of a pressure demand type so they quickly become useless much above a 20,000ft cabin altitude. Lowly pilots are not trained on how to prevent the masks from falling, just how to manually drop them if the automatic system fails. The pilots guide to circuit breakers says: IN=good. OUT=bad. Collared=paperwork.

 

[aqualung]

Easy boys, no need for personal attacks if you disagree with someone.

Will the triple make it to 450 - most likely it will depending on weight. Yes, that is above it's certified service ceiling. There are additional requirements for certification for flight above certain altitudes, so the certified service ceiling is not necessarily directly related to altitude capability. If the weight is low enough, there is plenty of room between Vmo and Vmin for flight at higher altitudes.

Yes, the transponder can be turned off via a switch on the panel. It also turns off the ADS-B.

O2 masks are a moot point. The chemical generators in the masks that fall from the ceiling only last 15 minutes and are not of a pressure demand type so they quickly become useless much above a 20,000ft cabin altitude. Lowly pilots are not trained on how to prevent the masks from falling, just how to manually drop them if the automatic system fails. The pilots guide to circuit breakers says: IN=good. OUT=bad. Collared=paperwork.

What he said ^

Very funny actually had me LOL.

N

 

[aqualung]

Transponders do not have an On\Off switch, but each has a circuit breaker in the cock house.

Sorry, but this is the comment that riled me.

I had been polite and non personal up to that point.

THAT comment was not warranted.

N

 

[KYpatriot]

Ah boys, its all good any real man ought to be able to take a punch in the face from another man and then have a beer together later. Yeah its a cockpit, and whatever that implies is ok with me!

Of course nowadays it could be a boxoffice instead, and I hear they hold grudges...

 

[66427vette]

Willing to bet our secret spy programs know exactly where it is. No one wants to show what they really can do.

 

[c1steve]

Willing to bet our secret spy programs know exactly where it is. No one wants to show what they really can do.

If they do find it on the ground, intact, you are probably right in that no one would say a word until the situation is assessed and an interaction launched.

I still think they switched off the O2 generators via the circuit breakers and waited until the passengers died. Interesting that the O2 masks are ineffective above 20,000 feet. Next time I fly I not feel quite as secure.

 

[BoilerUP]

Interesting that the O2 masks are ineffective above 20,000 feet. Next time I fly I not feel quite as secure.

In the event of a loss of pressurization, the plane will be emergency descended below 20,000 *very* quickly.

 

[agent.john.smith.neo]

Gliding

Okay, so we know when the aircraft left KLA, it had about 8 hours worth of fuel. Now theoretically I was thinking if a pilot wanted to increase the range for a given fuel loading, one scenario came to mind. Which brought up some questions.

1. Can a pilot deliberately switch off all engines while cruising? Complete shut off?
Shutting off would turn the aircraft into a glider. The glide ratio for the 777 is I think about 18, assuming the it was cruising at FL350 when the engine is shut off and the pilot lets it glide till FL100, that would allow the tub to fly about 130KM. At this height he restarts the engine, takes it back to FL350 and lather rinse repeat. Which brings me to my next question.

2. Let us say the aircraft was cruising at 400 knots or whatever is the most fuel efficient speed, when it began gliding. What would be its speed after losing 25000 ft. Assuming it is glided perfectly.

3. How easy is it to restart an engine midflight? Mind you this engine was shut off deliberately there is no fault with it and one would expect that it would restart relatively easily. I understand the aircraft will have to perform a tricky maneuver mid flight by pointing the nose down picking some speed and then trying to start the engine. How difficult is it?

4. Also compared to just flying consistently at FL350 how much more or less fuel efficient is it to restart an engine at FL100, take it to FL350 and shut off and glide back to FL100. Mind you the total distance covered like this would be 130KM plus whatever distance the aircraft covered while ascending from FL100 to FL350. Is the the fuel consumption like this more or less than simply cruising at FL350?

This is an interesting scenario. There have been commercial aircrafts in the past which have had to glide due to various reasons. Most famous being the Gimli Glider. For the record I am not a pilot. Was bouncing off a scenario in my head.

 

[KYpatriot]

It is not more efficient to glide for awhile and then climb, though it would not be a particularly difficult thing to do. The most efficient no wind profile would be to stay as high as possible until an idle descent to your destination. When you glide you can do so at any speed you want, but the faster you go the more altitude you would lose per mile. The most efficient engine out glide speed depends on a constant that is determined by the shape of the wing and the aircraft weight, then adjusted for headwind or tailwind. It is usually no problem to restart an engine in flight, but you would need to be at a lower altitude, an average for big aircraft might be 25000 or less for consistent light off of the engine.
Good thoughts, but your scenario would use more gas, not less.

 

[agent.john.smith.neo]

It is not more efficient to glide for awhile and then climb, though it would not be a particularly difficult thing to do. The most efficient no wind profile would be to stay as high as possible until an idle descent to your destination. When you glide you can do so at any speed you want, but the faster you go the more altitude you would lose per mile. The most efficient engine out glide speed depends on a constant that is determined by the shape of the wing and the aircraft weight, then adjusted for headwind or tailwind. It is usually no problem to restart an engine in flight, but you would need to be at a lower altitude, an average for big aircraft might be 25000 or less for consistent light off of the engine.
Good thoughts, but your scenario would use more gas, not less.

Could you maybe give me a few numbers for the fuel consumption in cruise mode and fuel consumption while an aircraft is in ascent? Also if you have any numbers for an idle descent, that would be great.

 

[rrflyer]

Never flown a 777 but in the most general terms double the fuel burn during climb than normal cruise. For flight idle decent maybe half normal cruise fuel consumption.

Bottom line it takes an immense amount of power and fuel to push a airplane to altitude and the most efficient way to operate them is to climb high and sit there.


If your scenario worked some airline exec somewhere would be trying to make his pilots do it.




Again never flown the 777 but max altitudes are set for several reasons .... The airplane I currently fly would easily climb above its 45,000 foot ceiling but would be unable to descend fast enough during a loss of pressurization to meet certification regs.

The airplane I flew previously was certified to 51,000 feet but I've never talked to anyhow who could actually get it there.....it just didn't have the wing or the power.

 

[agent.john.smith.neo]

Thanks for the response. Actually the way I look at it, even if it more economical, it is not feasible as a standard operating procedure because it would take some skill to execute it. It is inherently dangerous, turning off both engines is not recommended, (that's like going downhill in a turned off car in neutral, recipe for disaster) and of course there is the small matter of the effect of constant re-starting on the engine. Not to mention the effects of constant altitude changes on passengers would be like a ship getting tossed on high-seas. Given these constraints doubt any bean counter would even consider this plan even if it is more efficient.

 

[66427vette]

Can pilots request more fuel before they leave ?

 

[agent.john.smith.neo]

Never flown a 777 but in the most general terms double the fuel burn during climb than normal cruise. For flight idle decent maybe half normal cruise fuel consumption.

Bottom line it takes an immense amount of power and fuel to push a airplane to altitude and the most efficient way to operate them is to climb high and sit there.


If your scenario worked some airline exec somewhere would be trying to make his pilots do it.




Again never flown the 777 but max altitudes are set for several reasons .... The airplane I currently fly would easily climb above its 45,000 foot ceiling but would be unable to descend fast enough during a loss of pressurization to meet certification regs.

The airplane I flew previously was certified to 51,000 feet but I've never talked to anyhow who could actually get it there.....it just didn't have the wing or the power.

Actually now that I thought of the basic numbers. Assuming your numbers are correct that the fuel consumption during climb is twice than of cruise. As long as the gradient of climb is steeper than the glide ratio, I am sure we will end up saving fuel.

 

[ColoWyo]

Can pilots request more fuel before they leave ?

Yes. Usually with dispatch coordination. You still have to be below max take off weight, have obstacle clearance along your route if you lose a engine, and not be over landing weight when you get to your destination.

 

[BoilerUP]

All the talk about the plane descending to "nap of the earth" ignores the fact that the lower you are in a jet, the more fuel you are going to burn...which would serve to limit range. Additionally, modern twinjet airliners aren't like P-3 Orions where they are known to shut one (of four) engines down to increase loiter on station. The best way to increase range is to reduce thrust and slow down from normal cruise speed to an economy cruise speed.

As for fuel...I would guarantee Malaysian knows exactly how much fuel was on that plane at blockout and takeoff due to automatic ACARS transmissions.

 

[KYpatriot]

Boiler that's why I thought maybe they went low to avoid getting skin painted and didn't have the gas to make it to where they were headed and ended up in the water.

 

[BoilerUP]

Boiler that's why I thought maybe they went low to avoid getting skin painted and didn't have the gas to make it to where they were headed and ended up in the water.

Seems as logical as anything at this point...in fact, probably too logical given some of the ideas floated around right now.

 

[Darkside-Six]

Fuck you guys, Aleins took them.

 

[flounderv2]

One of the best theories I have read yet.

A Startlingly Simple Theory About the Missing Malaysia Airlines Jet | Autopia | Wired.com