Can anyone point me in the right direction of a tutorial of how to use the Cabin pressurisation system on Dave Maltbys BAC1-11.
I have tried allsorts to get it right but always get the cabin pressure warning about FL110.
Hope someone can help...
Thanks
BAC1-11 Pressurisation Procedure
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DispatchDragon
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Yep, that about covers it.
Basic operation is just to click the 'Safety Valve' switch to Closed. If you're a really advanced user you can select a required cabin altitude.
The Safety valve switch & pressure differential indicator are indeed on the overhead on the 1-11 510ED. The regular 1-11 has it all on the centre section of the main panel.
http://www.dmflightsim.co.uk/html/1-11/ ... CENTRE.htm
For any that may not fully understand what the pressurization system is doing, here's the basics... (Forgive any inaccuracy, I'm not an expert :think: )
When flying pressurized, you hold a higher air pressure inside, just as if you were actually flying at a lower altitude & that is known as your cabin altitude.
When flying unpressurized, cabin altitude simply changes with the aircraft's altitude.
The most comfortable conditions would be to keep cabin altitude near zero (sea level). But holding all that air inside would mean the pressure difference (between inside and out) rises to dangerous levels when flying at high altitudes.
So as you go higher, you let some air out (increase cabin altitude) & that keeps the pressure differential safe.
You get these gauges to play with...
Cabin Alt to Baro Pressure. Click the 'A' knob to select your required cabin altitude. Set required alt back to zero when you start descent.
Cabin Altitude indicator. Anything over 10000 ft gives a warning light and sounds the horn.
Pressure Differential indicator. Max level of 7.5 psi is marked in red.
Max psi is 0.5 psi if the outside pressure is greater than inside (negative pressure differential). The 1-11 allows you to start raising the cabin alt before takeoff.
Cabin Rate of Climb indicator shows how fast the cabin altitude is changing.
Normal max rate is about +/- 400 ft/min. 'R' knob on the Cabin Alt to Baro Pressure gauge alters the rate.
Safety Valve
Needs to be closed (air tight) for pressurized flight. Even though closed, it's calibrated to be forced open if the pressure goes beyond max limits.
After a pressurized flight, the Safety Valve is opened so that any pressure difference is settled before the doors are opened.
Hope that helps.
DM
Basic operation is just to click the 'Safety Valve' switch to Closed. If you're a really advanced user you can select a required cabin altitude.
The Safety valve switch & pressure differential indicator are indeed on the overhead on the 1-11 510ED. The regular 1-11 has it all on the centre section of the main panel.
http://www.dmflightsim.co.uk/html/1-11/ ... CENTRE.htm
For any that may not fully understand what the pressurization system is doing, here's the basics... (Forgive any inaccuracy, I'm not an expert :think: )
When flying pressurized, you hold a higher air pressure inside, just as if you were actually flying at a lower altitude & that is known as your cabin altitude.
When flying unpressurized, cabin altitude simply changes with the aircraft's altitude.
The most comfortable conditions would be to keep cabin altitude near zero (sea level). But holding all that air inside would mean the pressure difference (between inside and out) rises to dangerous levels when flying at high altitudes.
So as you go higher, you let some air out (increase cabin altitude) & that keeps the pressure differential safe.
You get these gauges to play with...
Cabin Alt to Baro Pressure. Click the 'A' knob to select your required cabin altitude. Set required alt back to zero when you start descent.
Cabin Altitude indicator. Anything over 10000 ft gives a warning light and sounds the horn.
Pressure Differential indicator. Max level of 7.5 psi is marked in red.
Max psi is 0.5 psi if the outside pressure is greater than inside (negative pressure differential). The 1-11 allows you to start raising the cabin alt before takeoff.
Cabin Rate of Climb indicator shows how fast the cabin altitude is changing.
Normal max rate is about +/- 400 ft/min. 'R' knob on the Cabin Alt to Baro Pressure gauge alters the rate.
Safety Valve
Needs to be closed (air tight) for pressurized flight. Even though closed, it's calibrated to be forced open if the pressure goes beyond max limits.
After a pressurized flight, the Safety Valve is opened so that any pressure difference is settled before the doors are opened.
Hope that helps.
DM
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DispatchDragon
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petermcleland
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Hi Dave,
Yes I agree with your basic summary but would add that the engines are being bled to supply an airflow into the aircraft and it has to go out again continuously...So the Pressurisation Control Valves work away to adjust how much they are open to let the air out. These valves would only close in the event of a failure to supply engine bleed air. If the supply fails then they would shut immediately and the cabin altitude would be stabilised but climbing slowly due to leaks...While the crew would be busy descending because of the failure.
Think of it this way...In stabilised pressurised flight at altitude the engines supply an air supply IN...This air must be let OUT at the same rate as it is coming in or the aeroplane would inflate like a balloon and burst. It is the job of the Pressurisation Control Valves to control that out flow rate to maintain the cabin pressure at a certain value dependant on the Altitude of the aircraft. The inflow from the engines will vary as the power settings of the engines are changed by the crew and as speed and altitude change. So the PCVs can be quite busy sensing and adjusting...One engine suddenly fails!...Immediately the PCVs respond to the lesser flow in by closing a bit to lessen the flow out.
Just as a matter of interest a window blowing out of Concorde at near 60,000 feet could be coped with...The PCVs would just adjust to reduce their outlet by the same amount as the lost window is letting out. That is why the windows on Concorde were so small...Bear in mind that ones useful conciousness at 60,000 feet breathing 100% oxygen is about ten seconds. This is because even with 100% oxygen, at that altitude the partial pressure of that oxygen is insufficient to make it pass into the blood. The only way for man to survive at 60,000 feet is to a) be pressurised or b) be pressure breathing.
a) is easy and we do it everytime we fly in an airliner...b) is extremely difficult and you need to practice it for about a week before you are competent. I have done b) and I promise you it is very hard to do.
It is important to remember that using a spacesuit is not b), it is a) because your spacesuit is fully pressurised like a little aeroplane fuselage so you are just breathing normally in there...Whoops, sorry for the lecture...Got carried away there :redface:
Yes I agree with your basic summary but would add that the engines are being bled to supply an airflow into the aircraft and it has to go out again continuously...So the Pressurisation Control Valves work away to adjust how much they are open to let the air out. These valves would only close in the event of a failure to supply engine bleed air. If the supply fails then they would shut immediately and the cabin altitude would be stabilised but climbing slowly due to leaks...While the crew would be busy descending because of the failure.
Think of it this way...In stabilised pressurised flight at altitude the engines supply an air supply IN...This air must be let OUT at the same rate as it is coming in or the aeroplane would inflate like a balloon and burst. It is the job of the Pressurisation Control Valves to control that out flow rate to maintain the cabin pressure at a certain value dependant on the Altitude of the aircraft. The inflow from the engines will vary as the power settings of the engines are changed by the crew and as speed and altitude change. So the PCVs can be quite busy sensing and adjusting...One engine suddenly fails!...Immediately the PCVs respond to the lesser flow in by closing a bit to lessen the flow out.
Just as a matter of interest a window blowing out of Concorde at near 60,000 feet could be coped with...The PCVs would just adjust to reduce their outlet by the same amount as the lost window is letting out. That is why the windows on Concorde were so small...Bear in mind that ones useful conciousness at 60,000 feet breathing 100% oxygen is about ten seconds. This is because even with 100% oxygen, at that altitude the partial pressure of that oxygen is insufficient to make it pass into the blood. The only way for man to survive at 60,000 feet is to a) be pressurised or b) be pressure breathing.
a) is easy and we do it everytime we fly in an airliner...b) is extremely difficult and you need to practice it for about a week before you are competent. I have done b) and I promise you it is very hard to do.
It is important to remember that using a spacesuit is not b), it is a) because your spacesuit is fully pressurised like a little aeroplane fuselage so you are just breathing normally in there...Whoops, sorry for the lecture...Got carried away there :redface:
Regards,
http://www.petermcleland.com/
Updated 28/8/2007
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http://www.petermcleland.com/
Updated 28/8/2007
My Channel
http://www.youtube.com/user/petermcleland?feature=mhee
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