Lear 60 drivers

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Roger, Roger

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Tire pressure AD issued.
http://www.avweb.com/avwebbiz/news/Lear60TireMaintenance_202689-1.html
I remember hearing some interesting stuff from those of you familiar with the Lear 60 shortly after that crash. Thoughts?

AvWeb said:
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Operators of Lear 60 aircraft will have to check the tire pressure every four days starting July 10. The FAA issued a final rule on Tuesday mandating the maintenance procedure after it was determined underinflated tires caused a cascade of failures that led to a charter aircraft running off the end of a runway in Columbia, S.C., killing four of the six aboard. The NTSB determined the tires blew during the takeoff run and took out sensors that controlled the thrust reversers, resulting in their automatic retraction just when the crew needed them the most. The pilot didn't know the reversers were stowed, and firewalled the throttles as the plane went through the airport fence and hit a hill on the other side of a highway. Bombardier has since redesigned the systems making them less likely to fail in a tire blowout.

The FAA said it discovered the tire failure rate for Lear 60s was about twice that of other bizjets so it rejected recommendations that the four-day inspection rule apply to all bizjets. On the other hand, it also turned down the NTSB's recommendation that Lear 60 operators be required to check the tires daily and to give that job to the pilots. There are about 250 Lear 60s in operation in the U.S.
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Kneejerk

The airplane made an overweight landing, didn't have the proper inspection, and then an incredibly fatigued crew made the wrong go/no-go decision. Contributing factors were the design and function of the squat switch.

The 60 has boatloads of power. A blown tire shouldn't be a reason for a high speed abort, and especially not after V1

AVweb article said:
The first tire failed about 1.5 seconds after the airplane reached V-1, the maximum speed at which the takeoff could be safely aborted. The captain's decision to then attempt a high-speed rejected takeoff "went against standard operating procedures and training," the NTSB said.
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If anything, remove the logic that auto-stows the TRs in air mode. The Hawker can fly around with a deployed TR all day every day, so long as you keep it below 150 knots.
 
...our 60 drivers have had to have a mechanic check tire pressure every 4 days (96 hours...period...not 4 flight days) for................a while. Has to be an A&P, too. Can't be the pilot.

This is new?:dunno:

-mini
 
minitour said:
...our 60 drivers have had to have a mechanic check tire pressure every 4 days (96 hours...period...not 4 flight days) for................a while. Has to be an A&P, too. Can't be the pilot.

This is new?:dunno:

-mini
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It used to be a SB, and now is an AD.

The other problem the crash crew had was they had not checked the tires in over 3 weeks. They estimate they were between 80-100 PSI low on all mains. And the abort above V1 did them no favors.
 
ppragman said:
Its scary enough in the piston single! I had one go on touchdown felt it roll for just a second then BAM! it was everything I could do to keep the thing from going off into the snow drift. Sketch!
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Should have shut down the engine and retracted the flaps faster. Duh! :D:beer:

-mini
 
minitour said:
Should have shut down the engine and retracted the flaps faster. Duh! :D:beer:

-mini
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:D

I did pull the mixture, I left the flaps down because I hoped it would give me some modicum of directional stability. If it wasn't an ice covered gravel strip it would have been fine, but it was too slick. That was the only time I thought I was going to ground loop a tricycle gear airplane. Lol, it was cold as hell too, and I had to wait about 2 hrs to have someone bring a mechanic and a tire out to me. At least the lodge was open.
 
Hmmm, I didn't know the TR's stowed and the crew basically firewalled the throttles and made the bad situation worse.
 
pullup said:
Hmmm, I didn't know the TR's stowed and the crew basically firewalled the throttles and made the bad situation worse.
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That didn't help matters, but consider that they initiated the RTO at 149 KIAS; 13 knots above V1 (136 KIAS) and 4 knots above Vr (145 KIAS). The TR autostow shouldn't have even come into play.
 
TFaudree_ERAU said:
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If anything, remove the logic that auto-stows the TRs in air mode. The Hawker can fly around with a deployed TR all day every day, so long as you keep it below 150 knots.
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I think what you're proposing would be a kneejerk reaction. Just because a Hawker can do it below 150 doesn't mean that it would work on a Lear (or any other ac), and how often are we below 150? Personally I like that my ac has 3 locks (electrical/mechanical) giving plenty of redundancy that they're not going to deploy in flight.
 
Baronman said:
I think what you're proposing would be a kneejerk reaction. Just because a Hawker can do it below 150 doesn't mean that it would work on a Lear (or any other ac), and how often are we below 150? Personally I like that my ac has 3 locks (electrical/mechanical) giving plenty of redundancy that they're not going to deploy in flight.
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It's not that they deploy in flight, it's that they auto-stow with the loss of the squat switch. The PF brings the thrust levers to idle and picks up the piggybacks to deploys the TRs. Once deployed, the PF further pulls up on the piggybacks to command reverse thrust. The engines spool up and reverse thrust is applied. Just as the engines reach max reverse RPM, the tire blows, disables the squat switch, and the TRs stow. However, max reverse RPM is still being commanded. Basically, it's like the piggybacks have been stowed and the thrust levers pushed back up.

Not a good design.

I do give the NTSB credit for recommending that the piggybacks be made to match the actual position of the TRs, but lets see if Bombardier can weasel their way out of being required to redesign the system and once again allowing money to trump safety.
 
I have a friend who's a lear60 driver. He's always said that the lear60 has an overall bad design with the landing gear. Wheels are kind of undersized. Bombardier kept the same system as the 45 so there's added weight. He always complains that he can never get consitant smooth landings out the thing.:D
 
hrjet said:
I have a friend who's a lear60 driver. He's always said that the lear60 has an overall bad design with the landing gear. Wheels are kind of undersized. Bombardier kept the same system as the 45 so there's added weight. He always complains that he can never get consitant smooth landings out the thing.:D
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The 60 is older than the 45, so it's unlikely the 60 "kept" the same gear. Plus, the 45 and 60 landing gear are NOTHING alike. The 45 has "normal" sized tires, excellent brakes and trailing link gear.

Maybe he meant the 55.
 
hrjet said:
I have a friend who's a lear60 driver. He's always said that the lear60 has an overall bad design with the landing gear. Wheels are kind of undersized. Bombardier kept the same system as the 45 so there's added weight. He always complains that he can never get consitant smooth landings out the thing.:D
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TFaudree_ERAU said:
The 60 is older than the 45, so it's unlikely the 60 "kept" the same gear. Plus, the 45 and 60 landing gear are NOTHING alike. The 45 has "normal" sized tires, excellent brakes and trailing link gear.

Maybe he meant the 55.
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He actually meant the older Lears (31/35, and probably the 24/25, etc.). They all have the same brakes and gear as the 60 even though the 60 is a 23,500# airplane.
 
Now that I think about it might have been the older lears which makes it even more amazing since the Lear60 is pretty heavy compared. I think I was thinking about the 45 since he was saying its gear is a lot better.
 
TFaudree_ERAU said:
Maybe he meant the 55.
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Stone Cold said:
He actually meant the older Lears (31/35, and probably the 24/25, etc.). They all have the same brakes and gear as the 60 even though the 60 is a 23,500# airplane.
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Isn't the 55 an older airplane? :p

I haven't flown the 20 or 30 series airplanes, but from what I've heard, the brakes were pretty good for the weights they had to grind to a halt. I've heard numerous stories of 20 series airplanes being operated on 2,500'-3000' runways at light weights. On the other hand, the 55 is as much as a 21,500 airplane with all the available AMKs. Unfortunately, Gates dropped the ball by not taking the opportunity to improve the undercarriage. Since the 55 was basically an experimental aircraft leading up to the 60, the shortcomings were just passed on. The Longhorn wing was a new design, the cabin volume was greatly increased, the fuel system was simplified, etc etc...they just didn't do anything about the wheels and brakes.
 
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