Or is a damaged turbojet engine more inclined to compressor stall?

Anyone else on here have experience selling 20 series Lears? Was it common to take them up to 430 or 450 to see if the engines had issues?

I never liked being that high in a Learjet, remember this was about the time of the Payne Stewart crash.

I’m certainly no fan of 500 in a 650, in fact when he posted that I was like “wait, what? I thought the service ceiling was 450?” But, it turns out it’s 450 on the III and VI, but increased to 510 on the VII.

Flew our 25D in the mid 40's routinely, never seemed to be a big deal. I can also claim a brief stint at 510 in our 55, but, that was in the era before cell cams for proof.

One of our other pilots lectured me about no reason to be up there......uh, I was with the boss, and I was young and dumb, what did I know to say otherwise???

Flew our 25D in the mid 40's routinely, never seemed to be a big deal. I can also claim a brief stint at 510 in our 55, but, that was in the era before cell cams for proof.

One of our other pilots lectured me about no reason to be up there......uh, I was with the boss, and I was young and dumb, what did I know to say otherwise???

Uh, that is literally what you did.

Uh, that is literally what you did.

When I was a much younger man I knew two tail numbers - 20 series Lears - N23AM and N25AM. Anyone know those planes? I hope N25AM still lives somewhere - N23AM did the big smoking hole thing.

This is incorrect. It’s 510 on all 650s. Have thousands of hours in them and still fly a late 3 and one of the last 7s.

Craig

This is incorrect. It’s 510 on all 650s. Have thousands of hours in them and still fly a late 3 and one of the last 7s.

Craig

N25AM flew south, she was sold from CPN to a guy in Venezuela, December 2012, I don’t have any notes or activity after that.

While in college I worked as a data reduction technician in the experimental flight test department at Gates Learjet from 1976 to 1981. Lear did the 51,000 ft. altitude certification during that time and I flew on many test flights as part of that certification. I took video data of yarn tufts taped to the wing to study airflow characteristics at that altitude and mach. Learjet had “510” lapel pins made which stood for FL 510 and were given to those who had been to 51,000 ft. as part of the publicity for the higher altitude certification.

That is very cool and a great idea.

Chip-

It was years ago, so I have no idea as to ISA, but we would have been really close to gross weight in the examples.

Again, those charts make no sense because the X (I flew SN 127) only held 13000 # of fuel topped.

I see the charts, they don't agree with my real world experience at all but I can't fully explain the why . Part of it can be explained away by the lower left of the chart - the wind effect portion but not enough for the difference I saw actually operating the airplane.

They do look about right for what I saw through 430 or 430, but from there they make no sense. If you are at 430 @ ISA in 22 minutes, and the chart says you are sill climbing at 288 FPM, but then it says going from 430 to 450 take another 54 (81 - 27) minutes via a step climb, something doesn't add up.

I will see if I can find my old books and see if I can find the difference.

Brad

It’s been a long time, but I don’t recall any 20 series that were certified above 410. Why would someone take the plane above it’s certified ceiling to prove the engines can operate there? Might as well test it’s orbital reentry capability just because.

It’s been a long time, but I don’t recall any 20 series that were certified above 410. Why would someone take the plane above it’s certified ceiling to prove the engines can operate there? Might as well test it’s orbital reentry capability just because.