Carenado - Piper PA44 Seminole BAD STALL trying 16000ft?

User Support Hub Aircraft & Systems
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Carenado - Piper PA44 Seminole
’ Performance
Maximum speed: 193 mph (311 km/h, 168 kn)
Cruise speed: 187 mph (301 km/h, 162 kn) (75% power)
Stall speed: 68 mph (109 km/h, 59 kn) (flaps down) CAS
Range: 1,053 mi (1,695 km, 915 nmi) (55% power)
Service ceiling: 17,100 ft (5,200 m)
Rate of climb: 1,340 ft/min (6.8 m/s)’

Flying LUKLA to nearby airport, stalled out trying to reach 16000 ft per ATC directions
Mixture was at max thrust/power.
VERY BAD STALL

What’s wrong with this?
Flaps 1 to get to 16000 feet?

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Could very well need that…Weather, weight, wind and was baro set correctly or could you have been higher?
Also- Engine leaned properly, carb heat, prop settings
What does the poh state for the conditions you were in?
Search Bing for service ceiling for more info.
Stall should be expected/anticipated when way up there :slight_smile:

ATC is a work in progress :slight_smile: Use request lower altitude if your using atc instructions for now.

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Just to note that I do not have this aircraft so my input is based on general flying principles only.

Few questions/suggestions. But first a statement: absolutely by no means use flaps to try and reach the service ceiling. That is NOT what flaps are for and they will NOT help!

But your stall comment together with the flaps question raises a question for me: are you properly maintaining the appropriate maximum rate of climb speed when trying this? Some people seem to think you should try and maintain something near the maximum rate of climb while climbing and continue to pull the nose up as you get higher and the rate of climb diminishes. As the aircraft is incapable of maintaining that rate of climb, the speed will steadily drop until you stall.

Note that the max rate of climb is specified typically at or near sea level and drops off steadily as you climb. By the time you get to the service ceiling you would be lucky to be at 250fpm.

The other question pertains to mixture. When you say “Mixture was at max thrust/power”, do you mean that it was at full rich or do you mean it was appropriately leaned for maximum power at that altitude? Note that this question becomes irrelevant if you are using auto mixture.

Cheers

Alwyn

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Crept to level at 17,600 with about 35knt headwind, baro set per live weather(B key)
From about 15,000 to 16,500, climb rate appr. 200fpm
16,500 to 17,600 about 100fpm and dropping off.
Didn’t bother to set tas but ground speed 75-76knts.
Cowl flaps closed. No flaps of course.
45% fuel and total payload 450lbs(2xpeep +50 in DutyFree stuff)

…PA44 is probably a rental, so drive it like you just stole it!

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Set your altimeter to “standard”. I know that in USA transition level is generally 18,000ft but elsewhere it’s usually a lot lower. You may see your “service ceiling” then!

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Looking at this I’d say
the RL claim of a
Service ceiling: 17,100 ft (5,200 m)

is not met by the Carenado model

ah, well
I thought it was me

THX

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mixture shouldn’t be max at that altitude should start leaning from 3000 feet onwards …also were you on oxygen?

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Why do you say this? ccrbc got to 17,600. And having the 100fps rate of climb he had is not unexpected at or near the service ceiling. Rate of climb slowly reduces as you go higher until you reach the ceiling. It is also dependent on temperature: service ceiling is defined at ISA conditions.

And you did not answer my questions regarding airspeed and mixture, both of which are critical. And that would be INDICATED airspeed, not true or definitely not ground speed.

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Barring questions about properly leaned mixture, and configuration, which have already been covered here, an aircraft’s climb performance (and thus service and absolute ceiling) is highly predicated on aircraft weight, CG, and density altitude (pressure altitude corrected for nonstandard temperature).

At 17,000, the standard temperature is around -19°C. Currently the winds and temps aloft forecasts at altitude in that area are ISA+5. So that means a temp of about -14°C at 17000’, which gives a new density altitude of 17500’.

I have no idea your weight and balance situation, but the heavier a plane is, the lower it will top out. The more forward your center of gravity, the lower it will top out. Keep in mind as well that your best rate of climb speed (Vy) decreases with altitude and best angle of climb speed (Vx) increases. Where they meet is your absolute ceiling - you will no longer be able to climb and any further increase in AoA will induce a stall. And remember, this is variable based on the conditions I stated.

So you’re already playing on the margins of the plane’s ceiling, but now you’ve added ~500’ to the altitude it which “thinks” it is, plus unknown weight and balance factors. I’d say the fact it almost got to 16,000’ with a notch of flaps in (don’t do that) is pretty good.

For anybody else testing this, it helps to know the density altitude (altimeter setting and outside air temperature should suffice) and your aircraft weight and balance.

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means the RL plane gets to cruise at 17,100 ft (5,200 m) in a reasonable, rational, effective way,
not through the gymnastics hoops mentioned here by simmers.

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Please note people have been trying to assist when you asked a question. By not answering appropriate questions to clarify how you got into the situation you did and becoming aggressive to boot, you are really not helping your own cause.

Actually that means it is the highest it can fly under specific, standard conditions while being piloted competently in accordance with best practices. Quite frankly, if you stalled the aircraft while climbing, then you don’t know how to fly it competently.

If you consider knowing what conditions are relative to ISA and climbing at the appropriate speed with the aircraft leaned properly to be going through “gymnastic hoops”, you clearly do not understand the relevant concepts of flying.

And BTW, my questions come from real life flying background, not simming. The items I asked about are common knowledge for all private pilots, never mind commercial or ALTP’s. The reason I asked them is, because I do not own the Carenado Seminole, the answers to these questions would be an indication of whether the aircraft model is incorrect or whether incorrect pilot technique could not be the reason. Because yes, in real life and in the sim, aircraft sometimes do not meet the manufacturer’s specifications for a number of reasons. And secretfarmerGal’s somewhat tongue in cheek question re oxygen is also a clue as to how Seminoles are used in real life.

Good luck getting answers to your questions that you like.

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You’re on the money. I also come from real-world experience, having logged many hours in the Seminole while getting my AMEL certificate many, many years ago. Though I haven’t flown it irl in a long time, I still have the PIM and all the checklists.

Regardless, no matter what we fly, a plane is a plane and the things we’re talking about are fairly universal truths.

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I seriously doubt anyone here has taken a PA44 up to 17,100 ft with a stall warning in between

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A stall warning only comes up when you’re… guess what… stalling or being close to that. I relates to the angle of attack.

Look for the best climb speed Vx for your aircraft and hold it. Don’t climb with the VSI as a reference, only use speed.

MSFS has a very (VERY VERY) bad and entirely wrong implementation of mixture and since Carenado stubbornly uses nothing but default system I would recommend to activate automixture for such an undertaking.

This so called “cervice ceiling” doesn’t mean that your aircraft can always reach this altitude. It’s just certified for it. It depends on various factors such as weight, temperature, in reality even the quality of the fuel. But it also means that the aircraft can technically reach even higher altitudes, depending on [see above].

Fly on speed, that’s critical… If you get slower your angle of attack becomes higher which will increase your drag and you will possibly not be able to recover from that except by pushing the nose down which will likely result in a descent.

And… well, you got it yourself… Don’t expect a correct flight model from Carenado.

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By definition, as you approach the service ceiling, you will be very near the critical angle of attack. Any further increase will result in a stall. Those last 1000’ will be an extremely low climb rate and very near a stall. You will likely get indications of the stall (mushiness, turbulence as the flow separates at the wing root first, and stall warning) before you actually, fully stall.

That said, the first two indications are nearly impossible to simulate without tactile feedback, so we end up going right into the third. And the sim also has a tendency to overplay the effect of a stall, almost always immediately entering a violent, wing-dropping incipient spin as we get the warning.

I would fully expect an imminent indication of stall somewhere in the last few hundred feet of ceiling. And if you’re heavy, have a forward CG, or high density altitude, it’s going to happen far before 17,100’.

I had considerable, real-life trouble getting a Warrior to climb out of 6,000’ on a warm day at max takeoff weight (MTOW). Got out of ground effect and could only eke out 200 feet per minute and very much had minor indications of stall before I was able to steer toward lower terrain. I had about 2-3 kts between zero climb and stall indications. One of the scariest moments of my flying career and I learned a lot from it. Now, the Warrior’s max published service ceiling is around 14,000’, but if I’d had the room, I might have only been able to make 7500 or so.

Does this mean there was something wrong with the plane? No, it was entirely dependent on conditions: Earlier that same day, same aircraft, but 250 lbs lighter and 20° cooler, I was able to get it up to 12,000’ without a problem.

This effect of weight and density altitude kills a lot of pilots every year. Understanding these effects is crucial to aeronautical decision making. Understanding the difference between an imminent stall and a full stall and how that may present in slow flight is a key technical skill for a pilot that we practice all the time.

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Just a quick clarification: an aircraft’s service ceiling is the point at which it can no longer maintain a climb rate of at least 100fpm. It is not the point at which it can no longer go any higher at all.

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Right, that’s absolute ceiling, and you will struggle for the last bit of climb to service ceiling and absolutely have to claw for any additional altitude between service ceiling and absolute ceiling.

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There are many excellent posts here describing the various characteristics of an aircraft’s service ceiling, One thing not often mentioned in service ceiling discussions is that the service ceiling is determined by highly trained and qualified test pilots using equipment and engines fresh from the aircraft manufacturer. Sort of like EPA Gas Milage stickers on new cars.

There isn’t any good reason to attempt to fly to an aircraft’s service ceiling unless one is a test pilot. There is a design issue with MSFS ATC allowing ATC to issue a climb instruction to an altitude above the service ceiling of an aircraft. The best way to avoid this issue is to enter an accurate and valid altitude in the World Map flight planner nav log. The same recommendation applies to SIDs and STARs. These often contain altitude and speed requirements only obtained by airline jets. It is up to each pilot to verify their aircraft is capable to fly a SID or STAR.

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nope

‘It also depends on the certification by the manufacturer. I dispatch ATR-42 300’s. The “max service ceiling” is 25000′. The service ceiling is an operational ceiling and defined as the maximum altitude which can be reached with a minimum climb rate of 300fpm. This is the recommended cruise altitude to minimize the fuel consumption.’

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Nope. Manufacturers can impose different limitations based on operating requirements or other aircraft equipment, which is called an operational ceiling. The person who you quoted from Quora conflated the issue and based on the FAA definition, the answer was only partially correct. The language used to describe a service ceiling may be what the manufacturer calls it, but it is not, by FAA definition, the service ceiling.

By the FAA’s definition in the Pilot’s Handbook of Aeronautical Knowledge, the service ceiling for a piston aircraft is reached when it can no longer sustain a 100 fpm climb, the altitude of which, as discussed, is variable and primarily dependent on weight and density altitude.

But your quote is missing the point entirely. If you defined the service ceiling as 300fpm, then the service ceiling altitude would actually be much lower.

Here’s the climb rate chart for the Seminole, so you can see that it’s dependent on pressure altitude and temperature (density altitude), and weight (and, of course, it’s not going to be 100% accurate, every time, every plane, but close enough):

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