Challenger crash at KASE

[Capn Bloggs]

Originally Posted by LAA

Really? protects you? from what? an accelerated stall? I don't think so!! Please don't go around flying jets with such overly simplified rules of aerodynamics in your head.

Err, we had the manoeuvring speed concept flying the 146. Add 10kts (IIRC) and you're protected up to 45° (something like that; it was a long time ago). With a stall speed chart, it would be a simple matter to come up with basic additives to increase stall protection for bank angle, including your "accelerated stalls". So settle down and accept that there may be ways of operating aircraft that you don't know about.

[roulishollandais]

Originally Posted by lifeafteraviation

It's a crime to deliberately violate professional codes of conduct, established safety regulations or aircraft limitations when such reckless behavior results in a serious accident with loss of life and or property.

It may be a succession of negligences leading to that accident. The cost of an hour of flight for the operator is increased from 5 to 30% if the aircraft belongs to a financial organization. And the benefit for the operator is rarely more than 1%. (Being aviation operator is no a good way to make money). Imagine wath happens to the pilots' training time if you cán use these 5 to 30% or not for training!
Insurance is another trap in aviation : I wondered some airclubs staid very wealthy after crashes. An Aviation Insurer friend explained me that - at least in France and light aircrafts, I don't know for airlines and for bizjets? - aircrafts could be protected by insurance for a price which is higher of the value of the plane. 3 times the value is used typically. In case of total destruction of the plane, with killed people, if no fault can be found (the BEA report is used to show that) the responsibility is still limited by the law - The old myth that aviation is progress ! - you may buy three planes to replace the destroyed one's and the killed people). Such "clause" in insurance is legal in aviation but not elsewhere.

The safest operator belongs his planes, trains more his pilots instead paying interests rates to the banker or leaser.
Many bizjets who need to be leased or nead banks'help belong to people who consider their plane like a very sexy TOY, need them like drug, and don't fly enough to decrease the fix expenses. Another possibility in that case is to do a group of owners with different priorities to use it depending of common contract. But never let the banker become the owner, or one of the owner....

[maxphlyer]

Basic Aeronautical Knowledge

In case someone is interested in some basics:

G-force in a turn = 1 / cos of bank angle

Stall speed in a turn = square root of g-force


30 degrees - 1,15g - stall speed x 1.07
45 degrees - 1,41g - stall speed x 1.19
60 degrees - 2.00g - stall speed x 1.41


Always keep the blue side up!

Max

[lifeafteraviation]

fine, you tell me what speed would protect you and allow maneuvering at 30 and 45 degree bank, landing configuration. in terms of vref plus "X".

you select the jet.

or a series of jets.

and yes it is a simplification, and I don't have the numbers for every corporate jet? come on life, tell me. nice 'tude

OK..first of all....I apologize for the harshness of my post.

As maxphlyer pointed out...the math and physics is irrespective of aircraft type...but an accelerated stall can occur under such a wide variety of conditions that assuming you are safe simply by your bank angle and airspeed is a dangerous oversimplification.

The downwind turn you described is statistically the most common location for an aircraft to experience an accelerated stall....you airspeed is low, you are probably not yet fully configured for the calculated approach speed, and you are flying with a tailwind in reference to the ground causing the illusion of higher speed and the natural tendency to over bank. The math relative to Vref or Vap works as long as you are fully configured and you are maintaining perfectly level flight and there's no turbulence but that's unlikely. If your jet has an AOA this can be handy but it's difficult to pay attention so this is where crew resources are handy....have the non flying pilot monitor airspeed, bank angle, and especially AOA.

I know a guy who crashed a Lear25 exactly like this once...excuse me...."knew a guy."

In other words, going back to AC61-21A comes one of the most important sentences in basic flight training...."Stalls come from excessive AOA for the airspeed and not from the airspeed itself. A stall can occur at any airspeed, in any attitude, at any power setting."

- does that bring back any memories?

[maxphlyer]

Basics

Lifeafteraviation, I couldn't agree more!

[glendalegoon]

dear life after aviation:

it is nice for you to apologize for your harsh tone.

but perhaps you had not fully read my post?

I mentioned being fully configured for landing.

I spoke of visual miscues and a good copilot calling things like speed , bank angle and more.

I mentioned that the highest ground speed was at the point of highest bank so I would like to think I would be on guard as the higher the bank the closest stall (for a given speed).


Accelerated stalls can happen in level flight (if you work at it). Massive turbulence caused by orographic lifting might upset your plane.

BUT I gave many, many safety and protective methods to help someone attempting this maneuver.


I hope you will re read my post and look at all the protections I mentioned.

Your own post says: you are probably not fully configured


yet it is one of my first conditions.


FULLY configured because you have such a small area to circle and the slower the speed (CONSISTENT with stall protection) allows for a lesser bank angle than making the same maneuver with no flaps/leds and much higher speeds.

Mountain flying has its own visual mis cues or illusions as you put it. I've offered what I think is the most safe and protected method of circling to 33.

AND even then I've offered the attitude that you might have to get the hell out of there.

And I don't think I would try it in a non LED equipped challenger or other aircraft that couldn't circle, FULLY CONFIGURED at Vref plus 20 (or whatever your manual says) much above 140KIAS.

[West Coast]

I don't know where you guys get your information. I talked with a friend who is high up high up in the controller union-NATCA. No one has been fired, no controller actions are in question.

[bubbers44]

Who said the controllers did anything wrong? They report the conditions, it is up to the pilots to fly their airplane safely. All the controller can do to control what decision the pilots make is close the airport.

[Mad (Flt) Scientist]

Originally Posted by glendalegoon

...

I mentioned being fully configured for landing.

Just to comment on that for the challenger.

The FCOM states

Circling Approach
When performing a circling approach, maintain the airplane configuration from the final approach fix (FAF) onwards (flaps 30° and landing gear down).

(Flaps 45 is selected much laater in the procedure)

Flaps 45 is the full landing configuration, so a circling approach is already not fully configured. Unless you don't follow the FCOM procedure, of course.

Recognizing that your recommendation was in the abstract, not necessarily intended for challenger, but since that was the type in question, thought I'd add this info ...

[glendalegoon]

mad scientist

yes, and thanks for making it clear about the challenger.

the more I hear about the challenger, the less I like it.

I flew as a passenger on the crj which is sort of based on the challenger. sitting in back on climbout of IAD and in a turn to intercept an airway that I was familiar with, I could have sworn I felt a stall buffet .


be careful out there.

[galaxy flyer]

Glen,

Unless it was seriously mishandled, I doubt it was in stall buffer--the shaker would have been going.

The Challenger is fine, just operate it as the FCOM describes, not as if it were a different plane. Over the years, the wing hasn't changed much, but the gross weight has. Roomy cabin, 8 hours at .77 and cheap, too. I've been in and out of Aspen with one several times, too. Works fine, but it's not a Global, either.

GF

[bubbers44]

Lear or B757 we sometimes had to be fully configured on downwind for certain circling approaches. TGU it was required. You are too busy using outside visual references to be completing a check list.

[lifeafteraviation]

I read some of the stuff people say in here and just cringe. I can't quite figure out the motivation for posting some of this stuff....if it's a new pilot wanting to learn a bit more and needs to clear up some common misconceptions I understand and would encourage it but when it comes from someone claiming years of experience I feel a bit sick.

[lifeafteraviation]

the more I hear about the challenger, the less I like it.

I wouldn't discount the aircraft....I've never flown one but it's very popular and capable.

Most business jets don't have LED due to the complexity and the weight and that they don't really need it. Falcons do and they do very well on short fields but most aircraft are more limited by takeoff performance than landing performance so it does no good to be able to land in a significantly shorter runway than you can takeoff right?

Old Learjets being one of those exceptions....I think you could point them up and just takeoff from the ramp....I'm half expecting one old pilot here to claim to have actually done that.

[glendalegoon]

lifeafter aviation


I wish you would clarify your post about : CRINGE.

You mention, in your next post about planes that are limited by takeoff performance and it is an interesting point.

but the crash we have been discussing was limited by landing conditions. And you can't takeoff without landing first, unless its at the manufacturer's airport.

One of the greatest warnings a potential aircraft buyer should have is to fully understand WHY a certain kind of AIRPLANE IS CHEAP. GF mentions that the plane is cheap. And I'm not saying how it is built.

[lifeafteraviation]

glendalegoon, I really wan't talking about you. Your posts don't make me cringe. I may not agree with some things you say but that's all.

They are cheap to buy because they are dated I assume? I don't think they're cheap in the sense that they are low quality manufacture.

Most aircraft have many disadvantages compared to others....I mean there is no single perfect aircraft right? There's no point in adding complexity to an aircraft that would limit what is actually good at though. Some aircraft are good at being inexpensive to operate and that's a very important feature too although I wouldn't think the Challenger is near the top of this category.

[Capn Bloggs]

Originally Posted by LAA

most aircraft are more limited by takeoff performance than landing performance so it does no good to be able to land in a significantly shorter runway than you can takeoff right?

Err, no, LEDs also increase lift, therefore allow less speed, therefore steeper climb gradients (or less power/more weight for the required climb gradient) after takeoff, not to mention less takeoff roll if the runway is length-limited as opposed to obstacle-limited.

[lifeafteraviation]

Capn Bloggs:
Err, no, LEDs also increase lift, therefore allow less speed, therefore steeper climb gradients

Yes, that's exactly right. But let me digress further...

I was being a bit sarcastic because pretty much all aircraft can land in less distance than they can takeoff (notwithstanding 135/121 regulations)....thus my comment about the Learjet.

so...

That means takeoff performance is the larger selling point in most aircraft (since it's more limiting) and the Falcon 50 and 900 models are known for exceptional takeoff performance with LEDs and it's three engine design (better after an engine failure). But with most designs that lack LED it's more to do with reducing complexity and weight as long as takeoff performance is adequate for the missions involved in the target market. Otherwise you would encounter a point of diminishing returns very quickly which is why all jets aren't so equipped.

The other reason why LEDs may not be useful in a small twin jet design is the increase in drag and weight could actually negatively affect 2nd segment climb performance operating single engine rather than enhance it...or at best....be insignificant.

While takeoff performance may be enhanced by LEDs with all engines running, it may not be so much with half your engines inoperative after V1 and that's the limiting factor (at least for pilots who operate to those standards...some don't).

Dassault initially didn't use the full LED system as on the 900 when they introduced the super mid sized twin jet 2000 model for these same reasons even though they shared a common wing design (The 2000 series has a partial LED design).

The latest version of the 2000, however...the 2000S has actually increased the use of LED to obtain shorter field landing performance. This goes against pretty much everything I just said but Dassault had to modify the rudder to achieve this and the engines are more efficient than on the original design. Landing performance is still significantly better than takeoff performance but I wonder what use it is to land in less than 2000 feet when you need 4000 feet to takeoff. Interestingly, Dassault marketing emphasizes landing performance.

We could talk about this in another thread because it's interesting stuff....especially when you consider the 2000S slats are automatic when approaching stall to help mitigate the negative affects of inadvertently flying too slow while not yet configured...pretty cool stuff. F16s and other fighters use automatic LEDs to increase high speed lift during high G turns to allow a more dynamic range of corner velocity during a turning fight...to maintain a constant 9Gs while the airspeed bleeds off below Vc.

Getting back to ASE....this airport is really not a very limiting airport performance for takeoff (runway 33 only) and most jets will find takeoff performance at EGE to be more limiting due to obstacles.

As I said before....slats are a really cool selling point but so is purchase price and operating costs.

[lifeafteraviation]

Actually....here is what really sums it up....

"Pilots don't buy jets, rich people who don't listen to pilots buy jets!"

[glendalegoon]

airplanes become ''cheap'' because of their reputation after awhile. take an MU2 of the same year and a King Air same size and year, even discount that idea that the garretts are different than the pratts.

the MU2 is cheaper.

even though it is faster!

just wondering what the reputation is for the challenger.

And in some situations, circling or maneuvering in a confined area with gear down and full flaps makes a great deal of sense.

Not all circling approaches are in Kansas.


One mountainous airport, the only way in was to fully configure and spiral down over the valley east of the airport, go in, pick up pax, go out on the reciprocal runway, turn right 10 degrees, count 30, and spiral up to safe altitude , gear up and half flaps till over 7,000' and clear of all mountains. then, when clear resume normal flight.

sometimes you have to think like a pilot in the 1920's because all airports aren't nice and open with approaches approved by TERPS>

what did EK GANN say: singularly determined?