Airplane down at Addison (KADS)

Cooter said:
If there is no more power driving the rotor, what causes the increase in RPM? It seems like RPM could only be preserved, not increased. Is that an effect of simulating power loss for training that wouldn’t necessarily occur in a real engine failure?
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7uEukG4.png
 
overdrive148 said:
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The bottom picture would slow the blades with a positive pitch angle. That’s why he said you must unload the pitch immediately. It seems that only a negative pitch angle could increase rotor speed. Maybe there’s just enough negative angle to do that.
 
Same reason a gyrocopter's rotors turn as the aircraft is pulled forward by the tractor propeller.
 
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Cooter said:
The bottom picture would slow the blades with a positive pitch angle. That’s why he said you must unload the pitch immediately. It seems that only a negative pitch angle could increase rotor speed. Maybe there’s just enough negative angle to do that.
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No. If you leave the pitch full down you’ll over speed the crap out of the rotor system. There is an initial lowering of the collective and pitch up to establish the autorotation but once established you have to increase the blade angle to govern rpm and then manage pitch attitude to maintain the airspeed.
 
dtuuri said:
Hmm... props pull an airplane forward and a helicopter upward. If a prop suddenly goes to beta (ground fine?) I don't see any memory items or checklist here for it. If your helicopter blades do that have you got a checklist and memory items to fix it quick?
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A Beta range on takeoff would definitely make the airplane much harder to control than just a dead engine.
Isn't that what happened to Howard Hughes during the XF-11 test flight? (not on take-off, though)
 
Cooter said:
The bottom picture would slow the blades with a positive pitch angle. That’s why he said you must unload the pitch immediately. It seems that only a negative pitch angle could increase rotor speed. Maybe there’s just enough negative angle to do that.
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If you actually believe bumble bees and helicopters can fly, then you might believe that Fig. 2-47(c) explains how:

https://www.faa.gov/regulations_pol...helicopter_flying_handbook/media/hfh_ch02.pdf

Personally, I think they just scare the air molecules into surrender.
 
dtuuri said:
If you actually believe bumble bees and helicopters can fly, then you might believe that Fig. 2-47(c) explains how:

https://www.faa.gov/regulations_pol...helicopter_flying_handbook/media/hfh_ch02.pdf

Personally, I think they just scare the air molecules into surrender.
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Thank you for pointing to that specific figure. While I'm still convinced that your theory is accurate (like people, air molecules are afraid of helicopters and flee from them, causing the helicopter to levitate), this is the first time I've felt like I have even the most basic understanding of how the government-backed conspiracy theory of autorotation works.
 
Having flown both a C-90 King air and a Sikorsky S-76C++ during OEI (One Engine Inoperative) training, I can say that the King Air was easier to perform the immediate action steps during an engine failure after takeoff. Turbine engines can quit completely, fail in a low power condition, or at worst: high side and overspeed.

It takes a few more seconds to determine which engine has quit in a multiengine helicopter, but the power loss requires very precise and deliberate actions to avoid an unrecoverable condition. Airplane or helicopter, you only have a few seconds to either fly or land.

Sloppy or improper actions pretty much guarantee a bad result.

In many ways, I like single engine helicopters much more when the engine quits... Life is simple; you only have one choice. You land.
 
3393RP said:
CVR: Problem with the left engine voiced eight seconds before the crash.

That's sobering.
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That brings up a burning question in my mind... 8 seconds before the crash, would they not have still been firmly planted on the runway and could have aborted the takeoff?
 
Fallsrider said:
That brings up a burning question in my mind... 8 seconds before the crash, would they not have still been firmly planted on the runway and could have aborted the takeoff?
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Hard to tell, the NTSB specifically did not publish that information. Let’s assume end of recording is time of crash.

“Three automated "bank angle" aural alerts began about 3 seconds before the end of the recording.”

That means they were airborne and into the bank about 3 seconds before end of recording.

So x-8 seconds: problem communicated, five seconds later (X-3 seconds) bank is steep enough to trigger aural warning, three seconds later end of tape.

Until we know how many seconds before end of tape that liftoff occurred, I don’t think we can answer the question.
 
TCABM said:
Hard to tell, the NTSB specifically did not publish that information. Let’s assume end of recording is time of crash.

“Three automated "bank angle" aural alerts began about 3 seconds before the end of the recording.”

That means they were airborne and into the bank about 3 seconds before end of recording.

So x-8 seconds: problem communicated, five seconds later (X-3 seconds) bank is steep enough to trigger aural warning, three seconds later end of tape.

Until we know how many seconds before end of tape that liftoff occurred, I don’t think we can answer the question.
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That close to the ground, the “bank angle” call out triggers at about 15 degrees.
 
Is it just me, or does it look like there is fire before the impact from the dashcam video or is that just reflection off the plane?
 
Didn't see fire, but kinda looks like the left prop is in flat pitch. The airplane sure looks to be yawing significantly the last few seconds before it rolls over.
 
Goodness that is difficult to watch. Thing was practically flying sideways before it snapped over.

I watch stuff like this to learn. But man... just knowing the sheer terror those people felt in those last seconds makes my stomach turn.
 
Steve Costello said:
Goodness that is difficult to watch. Thing was practically flying sideways before it snapped over.

I watch stuff like this to learn. But man... just knowing the sheer terror those people felt in those last seconds makes my stomach turn.
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Thought the same thing. Right foot asleep?! Practically powersliding the airplane before it snapped over.
 
This is just horrible to watch. I think of all that these people did to fly safe. They purchased, by all accounts, a state of the art twin engine plane operated by a crew of two. Then in the blink of an eye they all perish. No icing; no thunderstorms, no crazy decision making, no density altitude issues. Sometimes just a bad set of circumstances conspire to trap you. I’ve read this thread from the beginning and other threads over on Beachtalk and obviously there are lots of opinions and it seems inevitable that some measure of blame will end up with the pilots, but when you watch the speed with which this situation occurs it’s hard to see anything but a SOL situation for which few would survive. Very very sad and my heart goes out to the families.


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Piston engines sometimes undergo infant mortality. There was a brand new Mooney crash din Texas, really messed up the pilot, though he's still on the right side of the grass. As complex as a turbine is, I suppose they could occasionally buy the farm catastrophically. Sad thing is, no matter the airframe or how good the pilot, some things can happen that just aren't recoverable.
 
Tommar98 said:
but when you watch the speed with which this situation occurs it’s hard to see anything but a SOL situation for which few would survive.
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Based on that video, I strongly disagree. I don't know why people are so meek about being critical of the dead. I'll digress since I'm not going to change minds here. This wasn't a widow maker scenario, not in the least.
 
When I go to sim school I usually get some time to really ask them to try and "kill" me good. An engine failure after rotation combined with an auto-feather fail(or inadvertently turned off) is a fun one. I can usually save it. However, I know it is coming(not which engine though), have rehearsed what I'm going to do, and have already been "flying" around on one engine for hours so I'm tuned in. If that were to happen IRL? I always brief it to myself before pushing the throttles up, but with so many variables and the surprise factor...it would be tough. The Vmca of the Conquest without bad engine feathered is well north of 130ktas, and I'm sure this KA350 is similar. There is a reason the system is required and why we test the system before every flight. I hope that isn't what caught this crew.
 
hindsight2020 said:
Based on that video, I strongly disagree. I don't know why people are so meek about being critical of the dead. I'll digress since I'm not going to change minds here. This wasn't a widow maker scenario, not in the least.
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I’m not qualified to evaluate the pilots handling of the scenario. I’ve read countless other’s opinions and it seems as I said pilots will be to blame. All I’ve read says this is vmc rollover. Just seems odd that all the twin drivers see this clearly yet an experienced pilot in the cockpit didn’t or somehow missed it. Stills sucks for everyone involved.


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Tommar98 said:
Just seems odd that all the twin drivers see this clearly yet an experienced pilot in the cockpit didn’t or somehow missed it.
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I don't grant much respect to so-called "experienced" pilots who "clearly" think the pilot err'd. North Central Airlines lost a Convair (and injured some passengers) on takeoff when (possibly) rudder cables stretched and they couldn't get full rudder travel. Planes have crashed when seats slid aft on rotation (cargoes too), so why not possibly when applying full rudder? Props have gone into reverse pitch under power (Howard Hughes). Maybe the pilot did err, but it's certainly not "clear".
 
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Can't believe how badly the airplane is skidding. Almost like they had the wrong rudder inputs or none at all. At least they didn't suffer.
 
Grum.Man said:
Can't believe how badly the airplane is skidding. Almost like they had the wrong rudder inputs or none at all. At least they didn't suffer.
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I'm amazed and how hard the airplane was skidding to the left before it paid off...
 
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Lowflynjack said:
I'm amazed and how hard the airplane was skidding to the left before it paid off...
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Any chance of a rudder gust lock not being removed? Just seems hard to believe that two pilots would both have sleepy right legs during takeoff.
 
SoonerAviator said:
Any chance of a rudder gust lock not being removed? Just seems hard to believe that two pilots would both have sleepy right legs during takeoff.
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There is a chance of anything but I doubt that was it, would make it pretty hard to taxi to the runway with it still on. My bet is pilot proficiency or complacency. After so many hours in advanced aircraft you start to forget you could still loose an engine. Even if the rudder was blocked, or some other malfunction happened they could have pulled the good engine back and had a shot at a better outcome. Of course that's easy to say watching from my desk chair.
 
Grum.Man said:
There is a chance of anything but I doubt that was it, would make it pretty hard to taxi to the runway with it still on. My bet is pilot proficiency or complacency. After so many hours in advanced aircraft you start to forget you could still loose an engine. Even if the rudder was blocked, or some other malfunction happened they could have pulled the good engine back and had a shot at a better outcome. Of course that's easy to say watching from my desk chair.
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I guess I always imagined the KA350 using a tiller for the ground steering.
 
Grum.Man said:
My bet is pilot proficiency or complacency. After so many hours in advanced aircraft you start to forget you could still loose an engine.
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How dare you cite Occam's Razor as the likely culprit, you heretic! :rolleyes::D

The King Air is a pussicat. Frankly, that video is a compliment to that airplane. I mean that in earnest, incendiary (no pun intended) as it may sound be to the "don't criticize dead people" crowd.
 
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