Max altitude
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Most twins can fly at least at 20000ft.
I wondered why the DA42 was limited at 18000ft.
Is it really an issue for flying IFR in Europe? I tend to think so, but I'm not exeprienced enough in IFR flying to form a opinion about it.
I wondered why the DA42 was limited at 18000ft.
Is it really an issue for flying IFR in Europe? I tend to think so, but I'm not exeprienced enough in IFR flying to form a opinion about it.
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Most twins can fly at least at 20000ft.
I wondered why the DA42 was limited at 18000ft.
Is it really an issue for flying IFR in Europe? I tend to think so, but I'm not exeprienced enough in IFR flying to form a opinion about it.
I wondered why the DA42 was limited at 18000ft.
Is it really an issue for flying IFR in Europe? I tend to think so, but I'm not exeprienced enough in IFR flying to form a opinion about it.
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Though I have not done the type by type research, I think you would find a number of twins which are either not permitted, or not at home as high as 18000 feet. Though operation up there may be possible, it's really not a very nice place to be for very long. Even with supplemental oxygen, you'll get a headache, and otherwise just know that you're somewhere that your body does not want to be. I've crossed the North Atlantic four times in unpressurized aircraft between 15,000 and 18,000 feet, and after a few hours, you just want to be down again.
Yes, you might choose to hope over weather, or a mountain range, but even that is a rare need, and the aircraft manufacturers know it. If you're having to climb to 18,000 feet to clear weather, you're probably pushing your weather luck anyway.
During my certification testing work with Diamond, I remember having these discussions with respect to the DA-42. But, I don't really remember the content, as it was not relevant to what I was doing anyway. But many things are the aircraft manufacturer's choice, and it really simplifies their certification, and business in general, to just limit certain operations.
Yes, you might choose to hope over weather, or a mountain range, but even that is a rare need, and the aircraft manufacturers know it. If you're having to climb to 18,000 feet to clear weather, you're probably pushing your weather luck anyway.
During my certification testing work with Diamond, I remember having these discussions with respect to the DA-42. But, I don't really remember the content, as it was not relevant to what I was doing anyway. But many things are the aircraft manufacturer's choice, and it really simplifies their certification, and business in general, to just limit certain operations.
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Suggest that the 18,000ft figure is related to the pressure altitude above which Decompression Sickness becomes an issue. Obviously this is a Cabin Altitude factor, so pressurised aircraft are not normally affected.
Breathing 100% oxygen can provide some protection above 18,000ft Cabin Altitude but only if correctly incorporated with a session of pre-breathing 100% oxygen before ascending. Clearly, this mitigation requires additional equipment to be installed in an unpressurised aircraft which raises issues of weight, cost, maintenance etc.
lm
Breathing 100% oxygen can provide some protection above 18,000ft Cabin Altitude but only if correctly incorporated with a session of pre-breathing 100% oxygen before ascending. Clearly, this mitigation requires additional equipment to be installed in an unpressurised aircraft which raises issues of weight, cost, maintenance etc.
lm
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Published flight manual limits are seldom where things go to worms, and generally where the manufacturer (and the FAA/EASA) have stopped testing because the number achieved meets the expected performance for the work the aircraft must do. Why is it forbidden to go beyond the values published? Because the FAA/EASA do not permit operations beyond that area proven to be safe and compliant.
This is true of speed, altitudes and most other published limits. Seldom does a published limit become that because above it things blow up. The one exception is probably CG, where the limiting value is sometimes that were control limits are reached somewhere in the envelope. But if the aircraft is somewhat over designed, and makes the planned CG handily, the manufacturer might just stop there, preen his feathers, and publish the limit.
This is true of speed, altitudes and most other published limits. Seldom does a published limit become that because above it things blow up. The one exception is probably CG, where the limiting value is sometimes that were control limits are reached somewhere in the envelope. But if the aircraft is somewhat over designed, and makes the planned CG handily, the manufacturer might just stop there, preen his feathers, and publish the limit.
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Except that a Cessna 150 is certified to CAR 3, not FAR 25 or CS-23.
Having owned one for some 20 years, the Cessna 150's maximum altitude is limited by power, certainly not by Mach.
As an aside, I thought about getting the 150 HP conversion with a service ceiling of 23,000 ft. -- Just think a CE-150 calling center with "XYZ at FL210, requesting higher."
The Goldfish
Having owned one for some 20 years, the Cessna 150's maximum altitude is limited by power, certainly not by Mach.
As an aside, I thought about getting the 150 HP conversion with a service ceiling of 23,000 ft. -- Just think a CE-150 calling center with "XYZ at FL210, requesting higher."
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Having owned one for some 20 years, the Cessna 150's maximum altitude is limited by power, certainly not by Mach.
I thought about getting the 150 HP conversion
The 150 HP 150 is nice, as a float or ski plane, to be flown with a fine prop, for more "up and out" performance, but little expectation of faster or higher. But the 172 (or 170B) will get you to about the same place for the same cost.
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CS 23 max altitude limitation
So much confusion! I rarely write on this forum, but given the valiant attempts to answer 172510's initial question I think it is merited on this occasion.
JOE-FBS was mighty close;
CS 23.1527 Maximum operating altitude
(a) The maximum altitude up to which operation is allowed, as limited by flight, structural, powerplant, functional, or equipment characteristics, must be established
Effectively the equipment characteristics limit the altitude, more in a bit, firstly let try and close off a few of the lines of thinking.
Handling Issue. Unlikely, if you can stay above stall speed then you may experience some degraded damping characteristics, but these are unlikely to define an altitude limit.
Engine Limitation. These are generally defined by temperature. As temperature varies hugely at altitude defining an engine limitation by altitude seems either overly conservative or inadequate.
High speed buffet. Just no.
Engine restart envelope. This is generally a smaller envelope than the flight envelope in terms of altitude and speed range, so won't be defining your top edge of envelope in any realistic scenario.
Oxygen. Yep. It's the characteristics of this system. In this Canular type system flight is limited to 18 000'. A mask is required
CS 23.1447 Equipment standards for oxygen dispensing units
If certification for operation above 5486m (18 000 ft) (MSL) is requested, each oxygen dispensing unit must cover the nose and mouth of the user.
So without a mask certification limited to 18 000'. Hope this answers your question 172510
JOE-FBS was mighty close;
CS 23.1527 Maximum operating altitude
(a) The maximum altitude up to which operation is allowed, as limited by flight, structural, powerplant, functional, or equipment characteristics, must be established
Effectively the equipment characteristics limit the altitude, more in a bit, firstly let try and close off a few of the lines of thinking.
Handling Issue. Unlikely, if you can stay above stall speed then you may experience some degraded damping characteristics, but these are unlikely to define an altitude limit.
Engine Limitation. These are generally defined by temperature. As temperature varies hugely at altitude defining an engine limitation by altitude seems either overly conservative or inadequate.
High speed buffet. Just no.
Engine restart envelope. This is generally a smaller envelope than the flight envelope in terms of altitude and speed range, so won't be defining your top edge of envelope in any realistic scenario.
Oxygen. Yep. It's the characteristics of this system. In this Canular type system flight is limited to 18 000'. A mask is required
CS 23.1447 Equipment standards for oxygen dispensing units
If certification for operation above 5486m (18 000 ft) (MSL) is requested, each oxygen dispensing unit must cover the nose and mouth of the user.
So without a mask certification limited to 18 000'. Hope this answers your question 172510
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While correct, I'm not sure that the information provided by MilFlyBoy is necessarily applicable to the DA-42, in terms of altitude limitation. The DA-42 is not equipped with an oxygen system, therefore it has no need to comply with 23.1447, so this would not form the basis of an altitude limitation. The powerplant restart limiting altitudes are lower than 18,000 feet, so these too are not the basis of a limitation, 'cause it's already exceeded.
23.1527 states that the maximum altitude must be "established" . It is 23.1583, which requires the maximum altitude be a limitation, but it still does not require a reason for the selected altitude for th elimitation, just that here must be one.
So I expect this returns to the fact that a manufacturer is not required to state why an altitude limitation is imposed. I can state that a Lycoming powered DA-42 is capable of flight at 19,500 feet, 'cause I've done it during testing, but I think that version of the aircraft retains the 18,000 limitation too. I know that in Canada, other diesel powered aircraft were altitude limited based on the engine operating characteristics.
Perhaps this limitation is more "visible" to the OP, as most other CAR 3 certified types were never required to have a maximum altitude, so they just did not express it a a limitation. That could appear to make the DA-42 stand out, but all Part 23 aircraft would have this limitation expressed.
23.1527 states that the maximum altitude must be "established" . It is 23.1583, which requires the maximum altitude be a limitation, but it still does not require a reason for the selected altitude for th elimitation, just that here must be one.
So I expect this returns to the fact that a manufacturer is not required to state why an altitude limitation is imposed. I can state that a Lycoming powered DA-42 is capable of flight at 19,500 feet, 'cause I've done it during testing, but I think that version of the aircraft retains the 18,000 limitation too. I know that in Canada, other diesel powered aircraft were altitude limited based on the engine operating characteristics.
Perhaps this limitation is more "visible" to the OP, as most other CAR 3 certified types were never required to have a maximum altitude, so they just did not express it a a limitation. That could appear to make the DA-42 stand out, but all Part 23 aircraft would have this limitation expressed.
