Lear 25 Drivers

[cj610]

I was wondering if there were any lear drivers here that consistantly operate above FL410? If so, do you think that the lower fuel burn is worth your loss of speed? Also, what is the highest you have been in a 20 series Lear?

 

[avbug]

There's not much reason to operate above 410 in the 25. If you're light, performance wise it's not a problem, but who wants to sit up there using oxygen (and who really does??)?

Been to 450 in the 20 series (24 and 25), but there's generally not much point. Don't forget that the requirement for passengers to wear oxygen (not use, but wear the mask) above 410 is an aircraft limitation. Again, I bet you'd be hardpressed to find anybody that has required their pax to do it, but it's part of the aircraft limitations, and is required.

 

[KlingonLRDRVR]

Take a good look at your oxygen mask for a placard that limits you to 410 max don't know if yours does but I've seen them on some. Personally I don't think the risk is worth going above 410. Remember how quickly the time of usefull consciousness goes down from just 350 to 410. My bet its even quicker between 410 and 450 even with it on. We both know there are way too many smokin holes out there from Lears and/or Lear pilots with oxygen problems. Don't become a Statistic. Live long and prosper.

KlingonLRDRVR

 

[TurboS7]

Went to 510 once with a LR25 with -8A engines just for the fun of it, it had no economic value at all. I would go to 450 on the last hour of a trip, I found 430 to be a nice altitude. LR25 is a pig and it was a struggle to get anywhere near 410, I always flew it at 370 for the first couple of hours then went to 410. The newer LR25's with the dropped tips do a lot better. As for the high altitude flying you can see what it did to me by all my post.

 

[Neal]

Lear 25

We fly at 430 and 450 all the time in the 24XR and 25 If your on a long trip where fuel may be slightly tight it's worth every bit to get up to those altitudes. Unfortunately, every trip in those planes are tight on fuel.

Realistically not many people wears their masks at those altitudes. But if you don't have the 510 pressurization system with the emer press valves you better think long and hard about what is going to happen to you should you lose pressurization rapidly without you mask on or within about 3 secs of doning!

 

[LR25]

On long trips, 3 hours to touchdown, we would go to 450 every time if we could and .76-.77 mach#.

If you use .76 or so you can get about 1450 fuel burn on a 25 with -8 engines.

I found if you go to 450 just as little as 15 minutes or so you still save on gas.

O2 masks, thats another deal.

As far as depressurization, 410 to 450 aint going to make much difference.

I think the rule of going as high as you can and as fast as you can works for any 20 series.

LR25

 

[avbug]

The extra climb isn't worth it. 1,400 an hour at 410 at .81 or .82 is typical, and there's no reason to go higher to try to get it down any more, because it won't really come down much more.

Besides, much higher, and the monkey might freeze.

 

[Neal]

fuel

In the 24xr and 25b I regularly get it down to 1200 an hour at 430 and 450. Takes about 15 to 18 mins for the climb, depending on the controllers, and have to pull the throttles back at altitude to keep from exceeding .81 Thats a huge savings in fuel and worth going up there just for that savings.

We have many trips nonstop from cleveland to denver...so getting to 450 will make or break that nonstop leg.

My rule of thumb is to be in the flare at 3:15 as long as it's VFR at the destination. Any longer and your not leaving much room!

 

[avbug]

I can see that in the XR, as you have the extra fuel (hence XR), but the general rule for 20 series is that after three hours, you're a glider.

Anything less than 1,000 lbs on landing is emergency fuel.

 

[tdvalve]

In our 24D I like to be at 410 or 430 most of the time. Have found very little to be gained by climbing to 450, or by slowing below .80. If ATC cooperates, a 3 hour leg is reasonable. I have flown 3.3 on the hobbs without getting low fuel lights. But, with the typical restricted climbs and early descents, 2.5 is more comfortable. We keep the elastic-band O2 masks around our necks from takeoff to landing, and one of us will be on O2 above 410.

 

[Neal]

fuel

When flying a 20 series lear you have to know how to play the game with ATC. On those longs legs (3 hour plus) you need to stay at altitude until about 80 miles out then come down at thrust idle....to do this it might be recommended to file to an airport further than your destination then when 80 miles out from your desired landing tell atc you'd like to change your destination. Works like a charm!...although ATC gets pissed from time to time.

 

[Starcheck]

Lear 20's

410 usually works great for fuel with minimal difference between .77 and .80. Yes you can get the slightly lower burn at 430 or 450, but you're rolling the dice on flaming an engine out any time you venture above 410. The cj610-6 is very suseptable to flaming out with any turbulence or abrupt engine operation, though the -8a is less so.

Anyone out there ever try to top a Thunderstorm, and have one pop?

410 has the additional benefit that only one pilot has to be on O2 (135 rule).

 

[TurboS7]

I was coming up A315 once with a Lear at 390, just past Port-A-Prince, when we came upon a big TRW. I decided to go ahead and top it so I got clearance to 430. At about 415, bump, goes the engine, so down we go into the TRW. I had a new FO and his eyes were big as saucers. I told him to get clearance for us immediatly to 240, Port-A-Prince couldn't understand why we had to go down(I didn't want to declare an emergency as we were having a lot of engine problems at the company at the time)Finally he gave out clearance to 240. It was at night so I just steered away from the flashes as we went into the TRW, of course in that situation radar was useless.We came out of the overhang at about 280 in the clear. At 240 we relit and then requested climb up to 390, Port-A-Prince said no, you are fine at 240. So we maintained 240 until we got with Miami then climbed. The problem was that we consequently ran low on fuel and had to land at MYNN for fuel. The passenger, patient, and crew in back at no time knew that we had a flameout.
If you are having problems with flameout check the IGV and make sure all the linkage is working properly. All CJ-610's should be able to go to 450 no problem if everything is adjusted right. Some times the linkage is so worn that it just needs to be replaced.

 

[LR25]

We constantly flew in 40's and alot at 450, I never had an engine flame out on me.

But we also moved the thrust levers very gingerly up there to. We had an airplane that gave a hickup every once and a while up there but thats about it.

I have heard that the -8 engines are alot better for not flaming out as to the -6 and -4's.

 

[TurboS7]

If you have a good set of engine's they won't and shouldn't flameout , but there are still a lot of junk parts out there. Of course I am 6 years outdated as I havn't been in Learjet circles for that long.

 

[avbug]

"(I didn't want to declare an emergency as we were having a lot of engine problems at the company at the time)"