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-   Biz Jets, Ag Flying, GA etc. (https://www.pprune.org/biz-jets-ag-flying-ga-etc-36/)
-   -   N999LJ Learjet 60 crashes on take-off SC. (https://www.pprune.org/biz-jets-ag-flying-ga-etc/343916-n999lj-learjet-60-crashes-take-off-sc.html)

900-7X 2nd Oct 2008 12:19

what would Vs be...can you haul back and get into the air at 100 knots?

Not sure about the but in the 55 at the weight it would need to be for that departure, it's unlikely, since V1 would be in the neighborhood of 130 knots. In one engine operations Vr can't be less than 105% Vmu, so all of the tolerances are already pretty close.

Not sure what the previous post has to do with any of this. Different circumstances sitting on the ramp and different airplane.

sevenstrokeroll 3rd Oct 2008 19:27

I meant can you takeoff below V1...sacrificing the safety of one engine op to get off the ground and then deal with the blown tire.

oh, its not that important I guess, but you probably get the idea

900-7X 3rd Oct 2008 21:31


I meant can you takeoff below V1...sacrificing the safety of one engine op to get off the ground and then deal with the blown tire.
It's always a possibility. One of the issues that would pass through my mind is "We have a problem that's probably a blown tire....if it has caused any as yet undetermined engine or control surface damage...I don't want to be airborne at a very low speed that might be at or deteriorate to a speed close to Vmc and have a worse problem. Of course you really have to react and don't have that much thinking time. Then another issue isn't yet talked about is crew fatigue. This fight was leaving just before midnight local. What "body time" was the crew operating on? How much real rest had they had? There are rest time regulations but they're absurd and among other things don't take circadian rhythm into consideration.

Time will sort it out.

Lookforshooter 5th Oct 2008 18:13

It's all moot...with 8700 ft of runway...V1 comes pretty early on the runway, and they had plenty of time to stop if there was a pre V1 vibration from a blown tire. Any number of things can happen, and might have. First of all it was around midnight, dark and the crew was probably tired...they had a 5 hour trip ahead of them...second they were at max gross, topped off, and might have been slightly overgross. They might have sucked a bird, not produced enough power, accelerated slow, and simply got to the end of the runway, not getting to V1 and tried to stop the plane. It doesn't take 8700 ft of runway to get a Lear off the ground, so they must have tried to stop, and just did it late or just not well enough.

900-7X 6th Oct 2008 15:07


V1 comes pretty early on the runway, Explain "pretty early" And you KNOW what V1 was on this night and exactly how much runway was required for this particular takeoff?
and they had plenty of time to stop if there was a pre V1 vibration from a blown tire. This assumes that they KNEW it was a blown tire and didn't suspect perhaps an airframe issue
it was around midnight, dark and the crew was probably tired you obviously have access to their duty time records..and yep that "dark" thing has a lot to do with stopping an airplane. might have been slightly overgross. Nice of you to assume that they were operating illegally...perhaps this is your personal SOP?? They might have sucked a bird, none noted by inspectors not getting to V1 nobody has said what speed they achieved tried to stop, and just did it late or just not well enough. Ahah! The dreaded "pilot error"
It's this kind of presumptive claptrap that one would expect from the general news media. It's full of assumptions and unfounded judgments.
I joined this discussion board thinking that maybe there would be some more intelligent ideas brought forth here. I can see that it isn't the case in this instance.

Flintstone 6th Oct 2008 18:29

In the words of one of my old examiners "Son. The most dangerous thing in aviation in an untested assumption".

Time for the popcorn smiley http://i11.photobucket.com/albums/a1...ns/popcorn.gif

Lookforshooter 6th Oct 2008 20:20

Gentlemen: Rather the join in the 'Gee we really don't know' conversation...I decided to look up the numbers, do a weight and balance. About 2700 ft to get to V1...that leaves 6000 ft left over...max gross weight to go non stop to VNY, at FL400, landing very light on fuel. Go run the numbers then come back with something worthy to add. Oh, and just one more reminder, while your sitting there trying to protect the pilots...let's try to remember the passengers...

SNS3Guppy 7th Oct 2008 07:41


About 2700 ft to get to V1...that leaves 6000 ft left over...
Your mantra ever since you played as ssg...what did you come up with for an accelerate-stop distance...and based on what data? You claim to be a single engine "jet pilot" of late...whereas you don't fly the LR60 or other two-pilot aircraft, what data did you use? The distance to V1 isn't particularly meaningful. The distance to get there and stop, or to go...is.

Then again, your experience is on the microsoft flight simulator, and mishaps are relatively painless there.

Lookforshooter 8th Oct 2008 07:34

Oh Guppy, ...you're asking me the relevance of V1 with regard to a plane that overan an 8700 ft runway on take off? You asking the acelerate stop distance? What?...you think it's longer then 8700 feet, at midnight? Sorry Guppy, they weren't using Flex, they weren't running 25000 hour trend monitored engines, they didn't have a 200 hr FO in the right seat...but you know what? Who knows they might have tried to keep going for V1, and just ran out of runway...because, like you seem to believe...some pilot's feel that when they get to that magical number (V1)...the plane always flies....

SNS3Guppy 8th Oct 2008 08:11

Apparently you can't answer the question, then...or back up your data with a real source. That's all we needed to know.

Did you just use "flex" when talking about a Learjet? Please, say something else stupid; you're on a roll.

Lookforshooter 8th Oct 2008 16:44

Guppy as usual, your bringing down the thread. I ran the numbers based on a flight planning program I have, based on some research to get the actual peformance numbers ect. While V1/Accelerate stop were roughly 2700 and 5700 respectively.., given the numbers I had...the weight and balance was interesting in that a non stop trip to Vny probably put them slightly over gross based on passengers and typical bags that they had. That's based on max altitude that this airplane can fly at, against the winds going West..even if they had took it up stairs, without a step climp, as high as they could have, they would have landed somewhere with 1200 lbs...and my winds were lighter in the morning...not heavier at night. Go figure. Now go do your homeowork Guppy and stop being so antagonistic.

con-pilot 8th Oct 2008 22:34


Now go do your homeowork Guppy and stop being so antagonistic.
Getting some popcorn, this is going to be good.


(My money is on Guppy. :ok:)

SNS3Guppy 9th Oct 2008 02:53

I am rated in the Lear.

Whereas your claim to be a "single pilot jet pilot" in various posts tends to exclude you from a crew cockpit and therefore the Lear, and whereas your numbers are haphazardly thrown together with complete ignorance with respect to the loading of the airplane and it's capabilities...what you present is guesswork and of no credible value.

Your highly unprofessional and ignorant guesswork, as well as insinuation of over-gross operation is nothing more than speculation. This alone removes any semblence of credibility you might hope to have had in the matter.

This "flex" of which you speak is a term you know nothing about; in fact, it's a term you picked up and still misunderstand, from your rallying in the tech form as the banned poster ssg...when you rally against reduced thrust takeoffs. Did you do your calculations based on assumed temperature, based on real conditions prevailing at the time of the mishap? No. Nor did you use Learjet or Bombardier data. Did you try to come up with something based on "flightplan.com," or some other internet source, then?

The fact is that this mishap is being investigated by highly competent authorities who are expert in their field, and who will present the public with the facts at the appropriate time, when the investigation is complete. Not until.

You'd do best to stick to the facts you know...which for you means remaining completely silent.

Lookforshooter 9th Oct 2008 06:51

As usual Guppy, you wrote a whole lot of nothing.....

pilotbear 12th Oct 2008 11:53

I agree...why is there always some as****e who has to insult people for doing what this site is all about; Speculation, gossip and rumour. If you don't like other peoples postings and questions then switch your f*****g computer off and go and read your bible. :D
So, another plane crashed and some more people died, shame but it will happen tomorrow and the next day and the next. Open debate is healthy and speculation however wild may raise questions relating to this or another incident one day that may save a life.

Brian Abraham 12th Oct 2008 14:33

Mods, is Lookforshooter and pilotbear one in the same. Sounds like it.

900-7X 12th Oct 2008 14:53

Speculation without firm facts is meaningless. Insinuation that we're thinking of the pilots without regard to the passengers is just plain stupid. Assumption that the crew was operating illegally is unfair. I have to side with Guppy on this one. Reading the ideas here and adding my experience to the equation, Guppy is saying quite a bit, others are making emotionally based assumptions. Once again I can get useless information from Katie Couric and her cronies and expect more here.

Lookforshooter 12th Oct 2008 18:49

900 - I actualy agree with you..it's just that when a plane crashes at the end of a 8700 ft runway, underpower..it's hard to give the pilots a pass.

G-SPOTs Lost 12th Oct 2008 20:08

lookforshooter (or whatever you're called) and Guppy please can you give up the pissing contest and go get a room. This thread is in just as much danger of a) getting closed off like the last one where you locked horns or b) terminal thread drift....

please just stick each other on your ignore list - dead easy

900-7X 12th Oct 2008 20:48


900 - I actualy agree with you..it's just that when a plane crashes at the end of a 8700 ft runway, underpower..it's hard to give the pilots a pass.
Yeah I know and I'm not giving them a pass, I'm just not for prejudging without facts.


Accelaration - burst tyre - damage to squat switches - aircraft goes to air mode - abort procedure applied - although crew believes reverses are working, they are actually stowed and the thrust applied by the crew (thought to be in reverse) continues to impede braking.
Please tell me no.
Is there a throttle - bucket interlock that will prevent this? Can it fail?
This is a strong possibility.
No there's no throttle interlock.


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