The thumby feature is back. I've instantly used it. Still humming the pressurization song.

 

Regarding vololiberista's post, I still recall that Helios crash where the valve was left on manual and open (if I recall that correctly). Yikes. Hypoxia is a silent killer.

 

There was

about a pilot being talked down by ATC as soon as they've found out that the guy suffers from the effects and, fortunately, was still able to perform basic tasks. One can hear the alarm in the background all the time and, without the ATC guy, the pilot may not have made it.

 

There also was some other pilot (plane) helping. The video itself comes in very surreal. :unsure:

Ground mode - valves fully open, thus outside and inside pressures are equal.

Correct

 

Pre-pressurization mode on take-off roll - valves open as much as to allow for higher outflow volume than the packs bring in, thus decreasing the CA at a rate of 500 fpm.

Outflow valves are sealed for TO to prevent FOD ingestion. As to how the aircraft is pre-pressurized I'm going to put up my hands here and say I'm not entirely sure... I shall find out and get back to you on that one. It's one of the things we have to know it does and why it does it, but not how it does it...

 

Pressurization during the climb - the decrease of the CA continues gradually until it gets to 8000' (max. value), where valves open so much as to allow for the same outflow volume as the packs bring in, thus maintaining those 8000'.

 

Descent - the valves allow for lower outflow volume than the packs bring in, thus increasing the CA at a rate of 750 fpm.

Correct

 

Rollout - ~55 sec after landing valves fully open, thus increasing the CA to be equal to outside.

Correct

 

Regards,

Ró.

On my VC10 panel updates there are more than 50 variables controlling different aspects of pressurisation:-

Whether or not you have donned your mask - thrust augmenters - crew/pax oxygen supply - hypoxia etc

It's extremely complicated to model the entire system fully and correctly.

This code is just for the red emergency supply knob only.

<Gauge Name="Oxygen Supply switch" Version="1.0">
<Element>
 <Select>
<Value>(L:redpull,bool)</Value>	
	 <Case Value="0">
	 <Image Name="emergency_in.bmp"/>
	 </Case>
	 <Case Value="1">
	 <Image Name="emergency_out.bmp"/>
	 </Case>
 </Select>
</Element>
<Element>
 <Select>
<Value>(L:redpush,bool)</Value>	
	 <Case Value="1">
	 <Image Name="emergency_pressed.bmp"/>
	 </Case>
	 </Select>
</Element>
<Mouse>
 <Tooltip>Emergency Oxygen %( (L:redpull,bool) )%{if}Out (Press to Reset)%{else}%( (L:redpush,bool) )%{if}Test (hold for 5 secs)%{else}In (Press to Test)%{end}</Tooltip>
 <Cursor Type="Hand"/>
<Click Kind="LeftSingle+RightSingle+RightRelease">
 (M:Event) 'LeftSingle' scmp 0 == if{ (L:redpull,bool) 0 != if{ 0 (>L:redpull,bool) 1 (>L:Sound_button,enum) 0 (>L:Oxy_On,bool) 1 (>L:OXYGEN 100,number) 0 (>L:ox_press,number) 0 (>L:OxyFlow,number) 0 (>L:mageye,bool) } els{ 1 (>L:redpull,bool) 1 (>L:Sound_button,enum) 1 (>L:Oxy_On,bool) 0 (>L:OXYGEN 100,number) 4 (>L:ox_press,number) 4 (>L:OxyFlow,number) 1 (>L:mageye,bool) } }
(M:Event) 'RightSingle' scmp 0 == if{ (L:redpush,bool) 0 != if{ 0 (>L:redpush,bool) 0 (>L:Oxy_On,bool) 1 (>L:OXYGEN 100,number) 0 (>L:ox_press,number) 0 (>L:OxyFlow,number) (P:local time, seconds) 0.00 + (>L:barometric_equalisation,number) 0 (>L:mageye,bool) } els{ 1 (>L:redpush,bool) 1 (>L:Oxy_On,bool) 0 (>L:OXYGEN 100,number) 2 (>L:ox_press,number) 2 (>L:OxyFlow,number) (P:local time, seconds) 5.00 + (>L:barometric_equalisation,number) 1 (>L:mageye,bool) } }
(M:Event) 'RightRelease' scmp 0 == if{ (L:redpush,bool) 0 != if{ 0 (>L:redpush,bool) 0 (>L:Oxy_On,bool) 1 (>L:OXYGEN 100,number) 0 (>L:ox_press,number) 0 (>L:OxyFlow,number) 0 (>L:mageye,bool) } els{ 1 (>L:redpush,bool) 1 (>L:Oxy_On,bool) 0 (>L:OXYGEN 100,number) 2 (>L:ox_press,number) 2 (>L:OxyFlow,number) 1 (>L:mageye,bool) } }
</Click>
</Mouse>
</Gauge>

 

Outflow valves are sealed for TO to prevent FOD ingestion. As to how the aircraft is pre-pressurized I'm going to put up my hands here and say I'm not entirely sure... I shall find out and get back to you on that one. It's one of the things we have to know it does and why it does it, but not how it does it...

 

Regards,

Ró.

 

Invaluable! Thanks capt. Ronan!

 

Valves sealed on TO to prevent FOD ingestion sounds quite logical. I would also assume this is one the things that happen when you press that 'ditching' button on the OVHD

 

regards

This code is just for the red emergency supply knob only.

Yikes that looks complicated, I need to learn me some computer code, all I can manage is simple Java... :wacko: Fair plé for putting all that work in...

 

Regards,

Ró.

Invaluable! Thanks capt. Ronan!

 

Valves sealed on TO to prevent FOD ingestion sounds quite logical. I would also assume this is one the things that happen when you press that 'ditching' button on the OVHD

 

regards

For the ditching valve, it closes all exterior openings below the water line. You have to be careful before you push it though or you could end up with everyone's ears popping if the bleeds are on.

 

Regards,

Ró.

Hey Ronan,

 

Quick question regarding your airlines SOP regarding packs. All the outfits that I have been involved with stress to the crew that, packs off and maximum availbale flex be used if available, the logic being that the flight crew should be aiming for the lowest EGT possible on take off. also if TOGA thrust is used then a report must be made. So, pack1 should be on at THR RED & pack 2 on at the Accel Alt

 

This is based out in the middle east, I take it some airlines in Europe do it differently?

 

Cheers

Hey Rónán,

 

Quick question regarding your airlines SOP regarding packs. All the outfits that I have been involved with stress to the crew that, packs off and maximum availbale flex be used if available, the logic being that the flight crew should be aiming for the lowest EGT possible on take off. also if TOGA thrust is used then a report must be made. So, pack1 should be on at THR RED & pack 2 on at the Accel Alt

 

This is based out in the middle east, I take it some airlines in Europe do it differently?

 

Cheers

We typically leave the packs on and then do the maximum flex that the Captain is comfortable with. Indeed if full TOGA is used I'm required to enter it into the journey log. I'm curious though as to why yee wouldn't do a packs on APU takeoff, particularly given the warmer climates of the ME?

 

Regards,

Ró.

I'm curious though as to why yee wouldn't do a packs on APU takeoff, particularly given the warmer climates of the ME?

 

Beat's me Temps hit around 50-55c in the summer out here, although packs are off just before line up and back on pretty quick at thrust reduction so the cabin stays cool. As mentioned it's all about the EGT, perhaps it is something to do with the engines being leased.

 

Off topic, have you ever operated an A320 in +50c? With Packs on while at the gate a huge mist builds up in the cabin and can be quite alarming for the pax!

Beat's me Temps hit around 50-55c in the summer out here, although packs are off just before line up and back on pretty quick at thrust reduction so the cabin stays cool. As mentioned it's all about the EGT, perhaps it is something to do with the engines being leased.

 

Off topic, have you ever operated an A320 in +50c? With Packs on while at the gate a huge mist builds up in the cabin and can be quite alarming for the pax!

Whether the engines are leased or not, you'd still want to ensure that you extend their life as much as possible, so I don't entirely think that's the reason. We own practically all our engines AFAIK, but I really don't think that's the reason for it. I'd say it's a lot more likely to do with the ambient temp around those regions.

 

With regard to operating in temps of 50+C , you know the melting point of an Irish man is 20c right? The hottest places I've been would probably be MAD in mid summer, but haven't been there for years, once I got enough seniority I wouldn't touch that place with a barge pole, though I do remember being there once where temps were in and around the low 40's... Would indeed be alarming for the pax, would like to see that effect myself though, sounds cool... or hot? ^_^

 

Regards,

Ró.

Sure, I actually meant having packs off being mandatory would save engine life, no idea why pack to apu was never used.

 

Decided to check if anyone had made a recording on youtube. Found a video from the USA, the effect in the vid is nowhere near as bad compared to operating in extreme temps and humidity but it gives you an idea of the amount of mist pouring out of the vents.

 

 

Actually this is a much better example

 

http://www.youtube.com/watch?v=TpKcv3hv5U0

This one seems a lot more extreme.

http://www.youtube.com/watch?v=TpKcv3hv5U0

 

I've never personally seen anything quite like that, a small bit of mist yes, but those look like a sauna... :Hypnotized:

 

Regards,

Ró.

've never personally seen anything quite like that, a small bit of mist yes, but those look like a sauna.

 

It seems they have all (pax) seen it before, they don't seem in the least bit bothered by it.

It seems they have all (pax) seen it before, they don't seem in the least bit bothered by it.

Initially some passengers might worry but aircon mist doesn't smell as smoke or hydraulic mist does!

They really take the on-board entertainment a bit too far with that one. -_-