Hello to all, Finished reading the Manual for the Level-D 767 and I noticed something that quite didnt make sense to me. When in the procedures section it mentioned to have the Engine anti ice ON when icing/rain/snow/moisture ect. and when outside temperature is below -10'C . But then it mentioned the following: "When at cruising altitude and cruising speed if the altitude is below -40'C the anti ice for the engines are not needed". Is this a typo, or is there a reason for this? Does the Anti Ice need to be turned on at all times below -10'C? Also another quick question, Can the TAXI lights be on when the landing gear is retracted? The taxi lights are on the nose gear right? So if the gear is retracted whats the point of the taxi lights on? Many Thanks
David
P.S. whats a DE-RATED Takeoff/DE-RATE Thrust?
Full Version: Level-d 767
QUOTE(riversiderebel3 @ Jun 19 2008, 09:44 AM) 
" if the altitude is below -40'C
Is that the typo?
QUOTE(Kilrah @ Jun 19 2008, 12:45 PM)
Is that the typo?
Well I think it is. If it clearly says that the Engine Anti-Ice needs to be turned on below outside temperatures of -10'C. Then why should the Anti Ice not be turned on when the temperature is below -40'C that seems a whole lot colder to me. Why would it indicate that the Engine anti ice is NOT needed if and when the aircraft is at cruise with outside temperatures below -40'C. Would it not be colder below -40'C thereforre needed the anti-ice due to even colder temperatures? seemed weird to me. Does this mean that for some reason the engines are all ready hot enough at cruise that the anti ice is not needed?
Many thanks,
David
If I had to hazard a guess, I'd say that under -40°C there couldn't be enough humidity (in water vapor form) left in the air to cause icing, or something along these lines.
QUOTE(Kilrah @ Jun 19 2008, 04:56 PM)
If I had to hazard a guess, I'd say that under -40°C there couldn't be enough humidity (in water vapor form) left in the air to cause icing, or something along these lines.
An icing condition is considered when:
- OAT (Outside Air Temperature) is at or below 0ºC, AND
- There is visible humidity
Since the 767 flies at high cruise altitudes, up there, there's little visible moisture to be considered as icing condition. At high cruise altitudes an OAT of 40ºC is quite realistic, especially for the northern or southern parts of the globe.
Since at 35000ft there's no visible humidity, no need for anti-ice.
Then again at 15000ft with OAT reaching 0ºC, at or below 0ºC, and visible humidity (rain, dense clouds such as tower-cumulus or cumulus-nimbus, fog, and else) there's a big chance for you to get ice over the wings, at the leading edge, or the engine air inlet.
So there's no typo, its just the conditions.
In conclusion, yo gotta have but conditions, to get icing conditions. I.E., if you have OAT below 0ºC and there's no visible humidity, no need for anti-ice. If there's visible humidity but OAT is above 0ºC, no need for anti-ice either.
QUOTE(The Airbuser @ Jun 19 2008, 08:13 PM)
An icing condition is considered when:
- OAT (Outside Air Temperature) is at or below 0ºC, AND
- There is visible humidity
Since the 767 flies at high cruise altitudes, up there, there's little visible moisture to be considered as icing condition. At high cruise altitudes an OAT of 40ºC is quite realistic, especially for the northern or southern parts of the globe.
Since at 35000ft there's no visible humidity, no need for anti-ice.
Then again at 15000ft with OAT reaching 0ºC, at or below 0ºC, and visible humidity (rain, dense clouds such as tower-cumulus or cumulus-nimbus, fog, and else) there's a big chance for you to get ice over the wings, at the leading edge, or the engine air inlet.
So there's no typo, its just the conditions.
In conclusion, yo gotta have but conditions, to get icing conditions. I.E., if you have OAT below 0ºC and there's no visible humidity, no need for anti-ice. If there's visible humidity but OAT is above 0ºC, no need for anti-ice either.
- OAT (Outside Air Temperature) is at or below 0ºC, AND
- There is visible humidity
Since the 767 flies at high cruise altitudes, up there, there's little visible moisture to be considered as icing condition. At high cruise altitudes an OAT of 40ºC is quite realistic, especially for the northern or southern parts of the globe.
Since at 35000ft there's no visible humidity, no need for anti-ice.
Then again at 15000ft with OAT reaching 0ºC, at or below 0ºC, and visible humidity (rain, dense clouds such as tower-cumulus or cumulus-nimbus, fog, and else) there's a big chance for you to get ice over the wings, at the leading edge, or the engine air inlet.
So there's no typo, its just the conditions.
In conclusion, yo gotta have but conditions, to get icing conditions. I.E., if you have OAT below 0ºC and there's no visible humidity, no need for anti-ice. If there's visible humidity but OAT is above 0ºC, no need for anti-ice either.
Perfect... I my question was answered thanks so much! Now regarding the taxi lights: Do they need to be shut off when landing gear is retracted or does it not matter?
The ones on the gear will probably turn themselves off when the gear is retracted but the "turn-off" lights should probably be turned off.
Engine Ice protection - For my aircraft the Engine Anti-Ice goes on when Temp < +6ºC and dewpoint/temperature split < 3ºC or there is visible moisture. Below -25ºC SAT (or OAT), it is considered that no ice exists. For what it is worth, at a common crusing level of FL350 the ISA OAT would be -55ºC. But I have a difference with Airbuser. The coldest temperatures at altitude are where the tropopause is at its highest - and these are near the equator, not near the poles.
Now for De-rated thrust - the 767 has HUGE engines and a very large variation in it's take off weight. It is also designed to operate from a whole variety of interesting places and is therefore normally dramatically "over-powered" for most operations. So to save engine life, fuel, make a little less noise and make it easier to fly, you will set less than full power when you take off. You do this by setting a false temperature in the engine control system. This is called "De-rating".
PM
Engine Ice protection - For my aircraft the Engine Anti-Ice goes on when Temp < +6ºC and dewpoint/temperature split < 3ºC or there is visible moisture. Below -25ºC SAT (or OAT), it is considered that no ice exists. For what it is worth, at a common crusing level of FL350 the ISA OAT would be -55ºC. But I have a difference with Airbuser. The coldest temperatures at altitude are where the tropopause is at its highest - and these are near the equator, not near the poles.
Now for De-rated thrust - the 767 has HUGE engines and a very large variation in it's take off weight. It is also designed to operate from a whole variety of interesting places and is therefore normally dramatically "over-powered" for most operations. So to save engine life, fuel, make a little less noise and make it easier to fly, you will set less than full power when you take off. You do this by setting a false temperature in the engine control system. This is called "De-rating".
PM
QUOTE(Piltdown Man @ Jun 20 2008, 07:38 AM)
But I have a difference with Airbuser. The coldest temperatures at altitude are where the tropopause is at its highest - and these are near the equator, not near the poles.
Wow really?
I thought OAT's would be lower on the poles...since we can get here at FL350 like -29ºC or something like that...as a matter of fact, at 11000ft we commonly have an OAT of around 10ºC...
I'll re-check my weather textbooks, though.
Eduardo
Tropopause levels today Mid UK - FL350, -43ºC, Mexico City FL600, -60ºC, Greenland FL290 -34ºC.
PM
PM
Regarding taxi lights : Level-d's 763 switches the nose gear taxi lights off after reaching 60knts groundspeed. This is not true for its real life counterpart; however.
Great add-on by the way. Doesn't eat up resources either.
Cheers,
Chris
Great add-on by the way. Doesn't eat up resources either.
Cheers,
Chris
QUOTE(The Airbuser @ Jun 19 2008, 07:13 PM)
Since at 35000ft there's no visible humidity, no need for anti-ice.
Then again at 15000ft with OAT reaching 0ºC, at or below 0ºC, and visible humidity (rain, dense clouds such as tower-cumulus or cumulus-nimbus, fog, and else) there's a big chance for you to get ice over the wings, at the leading edge, or the engine air inlet.
So there's no typo, its just the conditions.
In conclusion, yo gotta have but conditions, to get icing conditions. I.E., if you have OAT below 0ºC and there's no visible humidity, no need for anti-ice. If there's visible humidity but OAT is above 0ºC, no need for anti-ice either.
Then again at 15000ft with OAT reaching 0ºC, at or below 0ºC, and visible humidity (rain, dense clouds such as tower-cumulus or cumulus-nimbus, fog, and else) there's a big chance for you to get ice over the wings, at the leading edge, or the engine air inlet.
So there's no typo, its just the conditions.
In conclusion, yo gotta have but conditions, to get icing conditions. I.E., if you have OAT below 0ºC and there's no visible humidity, no need for anti-ice. If there's visible humidity but OAT is above 0ºC, no need for anti-ice either.
Uh...not exactly....
Jet transport ops...at least where I drive...Temp below 10/5C and vis moist...Cowl/wing AI used as those are prime conditions for ice on aircraft. Below -40C, the temperature is such that anything frozen up there will remain frozen and not affix to the aircraft...regardless of the altitude or cumulu-whatzit clouds.
QUOTE(riversiderebel3 @ Jun 19 2008, 02:44 AM)
P.S. whats a DE-RATED Takeoff/DE-RATE Thrust?
It's a takeoff that given the circumstances (OAT, aircraft weight, airport elevation), you will not use all of the thrust that the engine can provide. So, in order to "take a good care" of the engine, and not using all the thrust when it's not necessary, you make a De-Rate Takeoff.
Ed
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