John, the straight wing Lears featured built-in divergent, negative lateral stability without a yaw damper. It wasn't a pilot problem, it was most certainly an airplane problem, even with a modified MKII, Century III or Softflite wing.*

All the wing modifications did were to lower the REF speed and make the stall characteristics less abrupt. A straight-wing Lear would pay off without any airframe buffett or aerodynamic warning at all. I'm not asserting that from personal experience, the people who've actually stalled a 20 or 30 series Learjet in flight with the original wing are no longer alive. (Pete Reynolds, Hank Baird, Etc.)

Couching this in terms of "resolved with a little pilot practice" are simply not true. a slow, configured Lear dutch rolling was easily correctable once you had the timing down. Much like the KC-135, and original 707's, not nearly enough tail. (They used to sit out in lawn chairs at Castle AFB in Merced and watch the student copilots try to wrestle it to the ground and have to go-around when the roll/yaw angles became to dangerously close to the limits) In addition, even with Mach trim, the shorter fuselage jets required the AP to be engaged above .74 and FL240 because the stick force gradient in pitch didn't meet part 25 requirements. (Still easily flyable) That's why the Lear 28 crew in the story upthread had the autopilot on, not because the airplane was challenging, because you'd have the overspeed horn screaming at you without it.

The stability issue is not having a YD at altitude or in IMC conditions. My memory of the Learjet MEL was that you had 2 yaw dampers installed, 1 required for dispatch. If you were going to defer one, it was day VMC, less than 10,000 feet and 250 KIAS or less.

Being able to dampen out a developing dutch roll on final was within the capabilities of a well-trained and experienced pilot. At altitude or on instruments, you could no-**** lose the jet.

Interestingly, I also flew 31's with the body locker and fuselage strakes. Those didn't need a YD at all. (Engagement optional)

Of all the variants, I only had the 31A to FL510. The sky was darker, the indicated Mach was slow, and fuel flows in the basement. You sure as hell couldn't see the curvature of the earth. Anybody who says they can is lying. Both of us had the O2 masks on.

The Lears were not that difficult to fly. They weren't even that fast. I can climb a light 767 to 410 in 12-13 minutes and level off well above the Lear's MMO. But they did have some built in weaknesses aerodynamically and if you didn't know the systems - fuel in particular - you kill yourself spectacularly fast. They didn't require any particular pilot talent, beyond knowing the airplane and flying the published numbers. If you were in a 20-series, you'd best have landing weather before you left altitude. The moment you pulled the thrust levers back, you list of available options shrunk to just a few.

*Modifications that put a blunt cuff on the leading edge, along with either VG's or BLE's in from of the ailerons and a stall fence. Or two.

I realize that the 20 series (tapered wing) Lears were naturally a bit unstable in aerodynamic terms, much as a Bonanza is in roll. I never tried flying without a YD at altitude, my comments were based on people who were afraid to turn it off until the wheels were about to touch. I turned it off in the pattern as a rule, and never had a problem keeping it flying nose-forward, but then I remembered what the rudder pedals were for; something that some jet drivers forget. I don't know when they started putting two yaw dampers in; our 23s only had one.

Full aerodynamic stalls are pretty close to what you describe. My only exposure was during a ride to calibrate a replaced AOA vane in a 25 with IIRC a Softflight wing, which required a series of stalls all of the way to the break. We were fairly low (not in the flight levels), but the result was little to no buffet, a sharp wing drop, and pitch down. Recovery was straightforward. The stall warning/AOA system was the same on the 23s, including those with the factory wing and so I'm pretty sure that those would need to be calibrated the same way.

When you say that the short body Lears "required" the autopilot to be on above .74 or FL240, I assume that you mean for certification. There was no such limitation in the flight manual, and I can tell you how tiring it is to fly a 23 with the factory wing, by hand, for over an hour at FL410 because the autopilot chose to take that day off. Even when I didn't have to, I would hand fly the climb to altitude, and the descent just because I enjoyed flying the plane. It was not difficult to control at high altitude, just very demanding of one's attention to avoid altitude excursions.

Once they equipped (or upgraded) the tip tanks with jet pumps fuel management became almost a non-issue. Left fed left, right fed right, crossflow and a boost pump pushed fuel across. Transferring into and out of the fuselage tank required a little planning, but I've seen Bonanzas that have far more complicated fuel systems.

Like any airplane, you have to know its systems and flight characteristics. I'm not suggesting that the Lear was a Citation, it was not, but neither was it the demon pilot killer that some would have you believe. Just like the stories of many other airplanes that "would kill you as soon as look at you", the truth is a lot less exciting.

Exactly.

Was fun to bitch about dispatch sending us out without an AP in the 35's in South Florida, but in reality it made the trip go by faster. And I could nail trim with highly refined 20yo something dexterity, amazing barrel trim selector coordination. I almost remember the little "bump" in the little trim selector.

Chub Cay back in the day after likely dropping off some good timing Texans. circa 2002. Was having the time of my life out of KFXE making beans and bagging chics.

It’s right over there…

I love that picture, Ryan. I spent almost six years of my life living and breathing all things Learjet. I've seen the CFR equipment through the windows of every model and crossed the North Atlantic in heading select.

It's difficult summing up the airplane. It's not the super high performance, deadly killer the ignorant and egotistical make it out to be. It was a very straight forward, honest jet.

What makes me grimace a little bit is when accomplished, smart guys like John attempt to frame the dutch roll as no big deal, just something any competent pilot can easily handle.

The jet had divergently negative longitudinal and vertical stability. It required a yaw damper to be dispatched. Although all of us who flew them have been trained how to dampen out dutch roll in the configured, lightweight, (Tips empty) arena, they were a whole different animal in IMC or at altitude without the yaw damper. Additionally, it's worth mentioning that the good old LR-JET didn't meet certification requirements laterally right out of the box, either. They required Mach trim, and a puller and you had to have the AFCS engaged above M.78 or the overspeed would sound. You were limited to FL300 and M.74 with the puller INOP. There were additional, draconian limitations if you were missing BLE's or VG's, but I can't remember them all.

My point being is that it was by no means a benign jet. Like many early designs, it had some areas that could bite, and no amount of good piloting technique changes that. How many other transport category jets can you think of where there have been at least two fatal mishaps involving loss of lateral control due to crew mismanagement of fuel?

I'm also highly suspicious of anybody who claims they could have flown it single pilot safely. Maybe a 31A if you added autothrottles.

I loved the airplane. I'd climb in a 35 right now with a competent partner and go flying. The jet is hard-wired to my aeronautical DNA.

It’s right over there…