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RV-6 Down due carb icing

AJ85WA

Well Known Member
Received an article on my news feed this morning regarding a RV6 that went down in September 2014

It was an interesting read and sure hits home as this could happen to anybody! Thoughts go out to family and loved ones.

Hope we can all learn something from it. Fly safe

http://www.atsb.gov.au/media/5747636/ao-2014-149-final_report.pdf

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gliding practice

A reminder to practice power-off emergency approaches, so you can do it if/when you need to.
Almost never a reason to extend downwind beyond the numbers if the engine isn't running.
 
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Survivability

Having worked as an accident investigator I have an interest in improving survivability through the design configuration of the cabin and associated equipment.

This is an area that I feel a lot of RV's dont do very well and probably reflects a lack of guidance material. So I was particularly interested to see that the report discussed survivability, hoping it might contribute some new learning that we could apply.

Then I read that the rear portion of the fuselage moved forward due to deformation on both sides of the cabin which reduced occupant space and probably also rendered the shoulder harnesses ineffective for upper body restraint. Seems to be an issue outside the builders control. But I would be interested in the observations of structures guys about where the deformation occured.
 
A reminder to practice power-off emergency approaches, so you can do it if/when you need to.
Almost never a reason to extend downwind beyond the numbers.

Spoken from a guy with a constant speed prop! If I perch at the numbers, I will land really long with a fixed pitch prop. The -4 is really tough to slow down.
 
Having worked as an accident investigator I have an interest in improving survivability through the design configuration of the cabin and associated equipment.

This is an area that I feel a lot of RV's dont do very well and probably reflects a lack of guidance material. So I was particularly interested to see that the report discussed survivability, hoping it might contribute some new learning that we could apply.

Then I read that the rear portion of the fuselage moved forward due to deformation on both sides of the cabin which reduced occupant space and probably also rendered the shoulder harnesses ineffective for upper body restraint. Seems to be an issue outside the builders control. But I would be interested in the observations of structures guys about where the deformation occured.

I don't disagree with the idea of making improvements to to aircraft with the goal being to improve crash survivability, but I don't think this accident is a good benchmark to start from.
I am not aware of any general aviation airplane where the occupants fair very well after a stall/spin at low altitude.

From the report.... ATSB analysis based on estimates of aircraft speed, impact angle, and energy absorption indicated that the impact forces imparted to the occupants would normally be expected to result in serious to fatal injuries. This statement precedes the findings regarding airframe damage, so my assumption is that they didn't mean to imply that the damage incurred is what changed it from survivable to non-survivable.

Looking at the in air photo and the photos of the airplane, it looks to me like a partial recovery was made because there is little damage to either wing and the airplane did move fwd a ways from the initial impact point. My arm chair guess is that spin to the left began (the airplane was in a left turn) which a partial recovery was made but resulted in a very high sink rate, but not steeply nose down impact. Odds of surviving that are rather low.

Low altitude loss of control is a primary killer regardless what airplane you are flying......
 
At engine idle a fixed pitch prop will indeed land longer then a constant speed prop. When the prop stops turning, which happens around 100 knots with an engine failure, there is not much difference between a fixed or constant speed prop.
Turn at the numbers, worst case is you land long and run off the end at a survivable speed.
I have had two engine failures with a fixed pitch RV4, and each time I was amazed at the descent rate. The first time I thought, based on engine running glides, that I woul be off the far end of the runway but in fact I landed close to the numbers.
The second time, having learned my engine out glide lesson, I landed in a soybean field with no damage to the airframe.
 
Guys, the real takeaway here is that not everyone is going to do everything just right 100% of the time. It's impossible and it's what accident investigators call Human Error. The reality of the situation is that anyone of us could find ourselves in this situation. You have to be on your game...all the time. Eventually, we may find ourselves in the wrong place at the wrong time. The goal of the skilled pilot is to do everything we can to prevent ourselves from getting into these kinds of situations in the first place.
This is a difficult reminder that in aviation we are playing with rules that are black and white and have zero flexibility. It's important to respect that concept every time we get into an aircraft.
 
Mixture knob position ?

On page 7 of the report, from the last paragraph

" During the on-site examination, the carburettor heat control was identified in the OFF position
(pushed in). It is possible that the impact sequence may have depressed the carburettor heat
control. However, surrounding push/pull controls were undisturbed in their pulled-out positions. "


On at least one side by side I have flown the mixture and carb heat knobs were identical in shape and texture. Only the color is different and I have on more than one occasion over the years, pulled the mixture by mistake. Thankfully the autopilot within has always reacted and just pushed it back.

However, the last sentence of the paragraph indicates the "surrounding push/pull controls were in their pulled-out positions. "

I would think at least the mixture SHOULD NOT have been found pulled out.
 
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C/S prop myth!

I know I will get flamed for this, but a C/S prop will NOT glide more slowly than a F/P. It may "help" you to slow down, but if you learn your airplane, a F/P prop can be landed just as short as a C/S.
 
Constant speed prop

Mel,

Not flaming....I do want to make a point. If you have the same aircraft in the same situation at the same airspeed, same altitude and same distance from the runway, the constant speed propeller equipped aircraft will land shorter with the same control inputs from the pilot. I agree that the pilot should know his airplane and cause all sorts of drag with slips and skids, etc. to get his airspeed low enough to land. I also agree that a pilot should never turn his back on a landing sight if the engine isn't running. It would be best to land fast and long and run out of landing space than to stall and spin in. Landing long will almost always be more survivable. Just my opinion.
 
I know I will get flamed for this, but a C/S prop will NOT glide more slowly than a F/P. It may "help" you to slow down, but if you learn your airplane, a F/P prop can be landed just as short as a C/S.

Mel, I was going to respond to this 'myth' but you beat me to it. :)

Learn airspeed management (pitch control) and a FP equipped RV can be landed near the numbers even if the perch is at the numbers. Basic airmanship.
 
Prop debates are moot in the context of this accident. He wasn't going to make the runway with any kind of prop. Caught low, slow, and deadstick, he should have accepted an off-airport landing....but mentally, it's hard to do. The runway is right there, and if I just pull a little.....
 
drifting to Dan

Dan, It might be in another thread.... so guide me if so.
On the subject of where our shoulder harness cables are anchored, is there any improvement to be had in the case of fuselage deformation?
 
Carb Ice Detector

Worth mentioning is that a carburetor ice detector really works. The one I have in my Cessna works so well I bought one for my RV-3B. It turns a light on when it senses ice. My experience is that is shows ice right at the beginning of its occurrence, with ample time to get carb heat on and well before I notice any effects myself.

It has a sensor in the carb throat.

Spruce sells them.

My only connection is as a customer.

Dave
 
The odd part is that they site carb ice.

With both of my engines (O-290 and O-360), I have found that when I slow down, the carb temp goes up to the point that carb heat adds nothing.

My thinking is that because of the lower air volume passing through the cowling, there is less air to cool the carb and the oil sump keeps the carb warm on Lycoming vertical sump engines.

As for the gliding distance, Dan is correct, the guy wasn't going to make the runway and should have given the plane to the insurance agent.

With my -9, if I turned base abeam the numbers while at pattern altitude, I'm not sure I could even touchdown on a 3,000' runway. I'll have to try that.

What I do attempt with every landing at our 2500' grass strip is to make only one power reduction and fly the entire pattern with the throttle fully closed. Thus, every landing is an engine out practice.
 
On the subject of where our shoulder harness cables are anchored, is there any improvement to be had in the case of fuselage deformation?

If we assume the shoulder belts are tight, it would probably take 12" or more of fuselage telescoping before the occupant's noggin struck the panel. I don't see anything like that in the photos. Without autopsy information, there is no reason to think either fuselage buckling or shoulder belt failure was a factor.

Do note that some reasonable degree of fuselage buckling is desirable. A shoulder belt anchored to a perfectly stiff structure would subject the restrained occupant to the entire g-load of the sudden stop.

Bottom line? Build to plans.
 
I know I will get flamed for this, but a C/S prop will NOT glide more slowly than a F/P. It may "help" you to slow down, but if you learn your airplane, a F/P prop can be landed just as short as a C/S.

Mel, I was going to respond to this 'myth' but you beat me to it. :)

Learn airspeed management (pitch control) and a FP equipped RV can be landed near the numbers even if the perch is at the numbers. Basic airmanship.

No flaming from me.... I totally agree.

I alternate flying a lot of different RV's with a mix of fixed pitch and constant speed props. As Sam said, airspeed control is the key.

The low aspect ratio wing of the rv's is prone to a big drag increase when the angle of attack starts to increase at slow speed. This has caught a lot of people by surprise and ended in damaged airplanes, but it can also be a useful tool to control decent rate.

It doesn't require slowing dangerously close to stall speed.... go out and practice at a familiar runway using a variety of approach speeds, working your way down towards 1.3 Vso. If you use 1.3 Vso for a major portion of the approach (starting abeam the numbers) and fly the approach pattern the same size you normally would, I bet you will find yourself adding power to make it to the runway, way before you are on short final. This proves that you don't have to go that slow. Now you can practice some more and learn to use airspeed as a tool to control power off decent rate.

Sorry for further contributing to the thread drift......
 
Not carb ice

The odd part is that they site carb ice.

With both of my engines (O-290 and O-360), I have found that when I slow down, the carb temp goes up to the point that carb heat adds nothing.

My thinking is that because of the lower air volume passing through the cowling, there is less air to cool the carb and the oil sump keeps the carb warm on Lycoming vertical sump engines.

Page 7 of the report , the last sentence, suggests the mixture knob may have been pulled out.

" During the on-site examination, the carburettor heat control was identified in the OFF position
(pushed in). It is possible that the impact sequence may have depressed the carburettor heat
control. However, surrounding push/pull controls were undisturbed in their pulled-out positions. "
 
I've come to appreciate over the years

that my 6A (at approach speeds ending in 65 MIAS over the fence) has the glide angle of a manhole cover with the flaps full out... probably because, although it has a better airfoil section than a manhole cover, it has almost the same aspect ratio.

All approach-to-final ops in the short-winged RV on the back side of the power curve need to be treated as a part of the roundout/flare - because they are, and you get only one try at energy management and descent arrest before the mains make contact. Back pressure only hastens the impact.

Master this, and you can land your RV like it's strapped on. Like you, Bill R., I pull power over the IP and don't touch it again until on the ground. Every overhead break landing is a practice engine-out into 2000 feet of sod, and this is the way you learn what works and what doesn't. It is also how you forget how to fly a rectangular traffic pattern, but that is another story.

-Stormy
 
Causal Factors and My Plan for Mitigation

Contributing factors/Mitigating Factors:

1. ?As the aircraft was turned onto the final approach to land, the engine ceased operating.?

a. Failure to imagine. I must expect my engine to stop running at the most undesirable inopportune moment and imagine how I will fly my aircraft as far into the forced landing under control as possible.​

b. Simulator training.​

c. Other?​

2. ?The meteorological conditions at the time of the accident were conducive to carburetor icing, which probably led to the engine stopping.?

a. GUMPS checklist.​


b. I have fuel injection but this still applies to me. My engine will stop someday. No denial here.​


c. Perform - Immediate Action Drills (IAD). A conditioned response to an unplanned event.​


d. Other?​


3. ?The steep turn onto the final approach at low airspeed probably resulted in an accelerated aerodynamic stall shortly after the loss of engine power from which the pilot was unable to recover before impacting terrain.?

a. Enter the pattern at the correct altitude.​


b. Fly a stabilized pattern/approach.​


c. While in the pattern, fly my identified pattern speeds/altitudes/sink rate.​


d. Keep my airspeed at an expectable margin above 1.3 Vso.​


e. I will not bank more than 30 degrees at low altitudes (pattern) with low airspeed.​


f. Other?​


Other factors that increased risk/Mitigation:

1. ?The aeroplane was not fitted with a stall warning device or angle of attack indicator, increasing the risk of inadvertent aerodynamic stall.?

a. I will add a quality AoA system that provides audio and visual ques.​


b. Other?​


2. ?The aeroplane was being operated at weights above the kit manufacturer?s recommended gross weight.?

a. I will not fly my plane over its factory specified gross.​


b. I need to lose weight.​


c. Other?​

I am deeply sadden by the loss of life in this event. I will carry the lessons learned from it with me and be safer for doing so.
 
If we assume the shoulder belts are tight, it would probably take 12" or more of fuselage telescoping before the occupant's noggin struck the panel. I don't see anything like that in the photos. Without autopsy information, there is no reason to think either fuselage buckling or shoulder belt failure was a factor.

Do note that some reasonable degree of fuselage buckling is desirable. A shoulder belt anchored to a perfectly stiff structure would subject the restrained occupant to the entire g-load of the sudden stop.

Bottom line? Build to plans.

Dan, In some of the NASA crash tests, they've caught severe and gross cabin buckling that rebounds when the load is removed. It's possible that what's visible in the photos is just the plastic (and permanent) deformation aftermath of such an otherwise elastic (and momentary) event.

Dave
 
Survivability

Scott and Dan's observations are spot on. We would need the injuries and the impact angles to better define the event.

The damage to the airplane suggests high vertical loading. The occupants were not involved in the panel. That usually means more downward loading than forward loading.

The fuselage buckling about the spar appears "downward", especially on the pax side. Look at the buckling around the spar. That appears to be the spar driving upward (or the fuselage downward). Same for the pilot side toward the leading edge. If the spar is being driven upward by the ground, your rear would be driven upward more by the ground (since your rear is in front of the spar).

On another note, there is no loss of cabin volume from a survivability standpoint. My impression is that the shoulder harnesses are not a factor.

The problem with our airplanes (any small airplane for that matter) is that there is no room for vertical attenuation. In a vertical loading, when your airplane hits the ground, you hit the ground (with some thin metal in between). Our airplanes are small, there is simply little space between you and the ground.

From the photos, I am guessing that the impact area has a good upward slope, thus the impact angle is the sum of the slope and the descent angle.
 
assumed engine stopped earlier

Spoken from a guy with a constant speed prop! If I perch at the numbers, I will land really long with a fixed pitch prop. The -4 is really tough to slow down.

Sorry, I should have been more clear, I meant that if the engine isn't running, don't glide past the numbers before turning.

In this case, it looks like the engine quit during the turn, so my comment doesn't really apply, other than to echo what David Domeier said, fly patterns so that if the engine quits, you can still make the runway. That may require a slip at idle power for F/P equipped a/c. I always flew my Citabria that way, it would glide so well I always seemed to be too high.
 
Dan, In some of the NASA crash tests, they've caught severe and gross cabin buckling that rebounds when the load is removed. It's possible that what's visible in the photos is just the plastic (and permanent) deformation aftermath of such an otherwise elastic (and momentary) event.Dave

That's a good point Dave. Static photos may not tell the whole tale.

Good example here; the tail cone deforms severely at impact, yet looks pretty straight after it all comes to rest. Go to the slow motion at 3:50:

https://www.nasa.gov/langley/second-crash-test-harvests-valuable-data-to-improve-emergency-response
 
Spoken from a guy with a constant speed prop! If I perch at the numbers, I will land really long with a fixed pitch prop. The -4 is really tough to slow down.

Possibly not if you were doing 60 knots and at 500 AGL. The key issue they raised was the pilots use of low approach speed. Even scarier was his steep banks at that low speed. They projected that he was in a 48 degree bank at 11 knots over stall speed. I guess this is just one more reason to keep the speed up on the downwind leg.
 
No flaming from me.... I totally agree.

I alternate flying a lot of different RV's with a mix of fixed pitch and constant speed props. As Sam said, airspeed control is the key.

The low aspect ratio wing of the rv's is prone to a big drag increase when the angle of attack starts to increase at slow speed. This has caught a lot of people by surprise and ended in damaged airplanes, but it can also be a useful tool to control decent rate.

It doesn't require slowing dangerously close to stall speed.... go out and practice at a familiar runway using a variety of approach speeds, working your way down towards 1.3 Vso. If you use 1.3 Vso for a major portion of the approach (starting abeam the numbers) and fly the approach pattern the same size you normally would, I bet you will find yourself adding power to make it to the runway, way before you are on short final. This proves that you don't have to go that slow. Now you can practice some more and learn to use airspeed as a tool to control power off decent rate.

Sorry for further contributing to the thread drift......

This is interesting for me as a new RV-6 pilot. Are you saying that a good tool to increase my descent rate, when necessary, is to reduce my speed to 1.3 Vs0? Is this preferred or more effective than a forward slip?

Thanks,

Larry
 
This is interesting for me as a new RV-6 pilot. Are you saying that a good tool to increase my descent rate, when necessary, is to reduce my speed to 1.3 Vs0? Is this preferred or more effective than a forward slip?

Thanks,

Larry

It is very effective but I'm not saying it should replace the skill of using a slip. I am saying it is something to learn and understand.

Once you understand it, you will be safer (not get caught by it) and you can learn to use your airspeed vs decent rate knowledge to make adjustment on approach.

I common trap I see with a lot of lower time pilots is doing everything in the pattern by rote process. I.E., always pull the power here.... always put the flaps down there, etc. Developing a process that allows you to fly stabilized approaches is good, but everyone is a little different because of winds, weight, etc.
Learning to gauge your approach and make needed adjustments along the way, using all of the tools available to you (slips, flaps, approach speed, etc) will make you safer.

BTW, 1.3 X Vso is too slow of an approach speed in the short wing RV's for all but situations requiring a very short landing. Particular those that don't have a lot of flight time in an RV. Maintaining 1.5 Vso until on very short final is a better choice (and I think what Mike Seager teaches)

I was recommending experimenting with slower speeds during the approach to see the effect, but save 1.3 into the round out for when you have a lot more experience.
 
Approach/Landing

Factory guidance recommends approach speeds of 1.3-1.4 Vs, which is slightly faster than the typical 1.3. "Vapp" is 5 kts/mph above "Vref" (1.3-1.4 Vs) to provide further energy and move a bit further to the right on the drag curve. This provides a base turn speed of approximately 1.5 Vs. This accommodates drag characteristics at high AOA/low airspeed. Short-field ops require slower approach speed and, generally, use of power. Sizing the pattern to adjust glidepath angle provides some additional flexibility (i.e., a steeper angle requires less use of power). A curved base turn (descending 180) technique can simplify flying consistent visual patterns that assist with achieving a stabilized final during the final 1/2 mile/3000 feet of approach, no later than "crossing the fence" window. It also assists with adjusting the pattern to accommodate ambient wind conditions using a visual skill set very similar to flying a turn around a point.

I've included landing discussion as a well as a depiction of a basic RV-type drag curve in the appropriate portion of the RV training materials in the safety section that goes into quite a bit of detail, which might provide some additional insight for folks that are interested. The 3000 AGL power-off "SFO" (simulated flame-out) pattern is designed to be a basic pattern (energy and ground track management) exercise, flying the airplane from 3K' over the desired touchdown point using the ONSPEED/Vapp to L/Dmax speed band (left half of the drag curve) and achieving stabilized final no later than crossing the fence without use of power. There is a sticky on the top of the safety page with a link to the current draft.

Fly safe,

Vac
 
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just to be clear

Charlie proposed:

e. I will not bank more than 30 degrees at low altitudes (pattern) with low airspeed.​

This is taught to avoid an accelerated stall with no room for recovery in the downwind to base and base to final turns, but such a stall requires exceeding critical AoA, not a critical bank angle. You can make even a knife-edge turn at low speed as long as you do not pull too hard. It's in trying to accomplish a levelturn at high bank angles that we pilots explore accelerated stall/spins too low to the ground. Let her have her head - let the nose drop if you need to - keep that G-loading down and you can make a more steeply banked turn close to Vso without an accelerated stall. Try to do it low and slow without altitude loss - refusing to withdraw some energy from your "altitude account," and your G-loading check will bounce with fatal results. If your engine is running, you replace that lost potential energy with a power increase to get you back on glide path. If it's a deadstick scenario, you don't have that option, and you must decide whether to accept a higher sink rate for a tighter turn, or to overshoot your turn while being able to glide longer and flatter without a stall.

The risk of refusing to bank at an angle appropriate for the turn you need to execute is the cross-control stall - from trying to cheat it with rudder while complying with the artificial bank limits your CFI drilled into your head. (Mine forbade bank angles over 20 degrees in the pattern.) You may bank as much as you need to for a coordinated turn in the pattern as long as you are careful how much you pull. In the pattern, whether banked or level, if you find you need more "pull" before you are actually in the flare, you must add power to keep your stall margin. If you need to pull and don't have power at your disposal, it's not going to be a good day, and your choices narrow to an off-field landing attempt, or an off-field crash.

FWIW, my subconscious mental dialog in the pattern is "I will make my turns as steep and tight as I need to fly the pattern I need, but I will not pull back on the stick to maintain the altitude and sink rate I want. Pitch is turn rate, power is sink rate." One gets there by degrees, with experience. The bank angle limits are like training wheels, and they come off with lots of practice both at altitude and down low. If you want to leave them in place your whole career, by all means do. Just watch for the cross-control stall if you overshoot a turn - don't skid.

-Stormy
 
FWIW, my subconscious mental dialog in the pattern is "I will make my turns as steep and tight as I need to fly the pattern I need, but I will not pull back on the stick to maintain the altitude and sink rate I want. Pitch is turn rate, power is sink rate." One gets there by degrees, with experience. The bank angle limits are like training wheels, and they come off with lots of practice both at altitude and down low. If you want to leave them in place your whole career, by all means do. Just watch for the cross-control stall if you overshoot a turn - don't skid.

Please....I have to speak up. This is bad advice and a bad mental approach to flying, no matter what aircraft one is flying. From a CFI standpoint, there is really on one realistic approach to flying traffic pattern work in general, and during power-off emergencies in specific.

It's true, Bill, that stall AOA is reached more quickly (in terms of decreasing airspeed) when--in a bank--the aircraft is held in level flight. When the vertical component of lift is reduced by sacrificing altitude to perform the turn, the critical AOA will be exceeded at a higher airspeed than during a level turn. Thus that ad hoc energy exchange would allow for a greater bank angle to be tolerated.

And it's all absolutely irrelevant, ladies and gentlemen.

A preponderance of GA accidents occur during low-altitude (traffic pattern, that is) maneuvering. Stall-spin scenarios are all too common, and we have to look at the causes.

The hypothesis that one can bank "as steep and tight as I need..." is woefully difficult to actually fly. The cause is that pesky math...the increase in stall speed in level flight with the addition of bank increases on a non-linear basis. An aircraft banking at 30 degrees will stall at just over 7% higher airspeed than in level flight. That same aircraft, flying at 45 degrees bank, will stall 19% faster. At 60 degrees of bank (easily and quickly attainable in a nice flying machine such as an RV), one can expect a whopping 40% increase in stall speed, e.g. from 55 knots to 77 knots.

The problem is that one cannot quickly do the mental math (Vstall accelerated = √G) while maneuvering in the pattern. Heck, I can't often do that math sitting at my desk!

The point is that we shouldn't make plans to do trade off altitude to be able to "pull harder" on the stick to make a turn successful. It's impossible to calculate just how hard to pull and exactly how much altitude one can sacrifice to make that pull "work" while performing an engine out recovery to a runway. Telling yourself to just 'feel the aircraft' is asking for trouble.

The reason? Simple...RVs are amazing aircraft, but--as a general rule--they do not provide much warning prior to the actual stall. Once it happens, the wing and/or nose drops and one must relax the back pressure (e.g. reduce the AOA) to get it flying again. While an AOA indicator will provide guidance on the subject, it is highly unlikely that one would have the cognitive capability during this stressful time to either monitor that gauge or even listen to a warning tone.

Recovery from that stall is simple...but it takes a little altitude, typically. And turning base to final in an engine out scenario is one place where altitude is at a premium. Please...consider the following advice.

1. Fly your traffic pattern (when practical) with the mindset that you can lose an engine at any time.
2. If you do lose that engine, maintain aircraft control. Slow to your best glide speed, attempt a fix if time allows (depending on aircraft...carb heat on, mixture full rich, fuel pump on, pump throttle)
3. Select a spot to land, then
4. Fly the aircraft to that spot--and don't exceed 30 degrees of bank to do so!

If that bank angle constraint won't get you to the runway, simply find the best landing spot ahead or close to your present heading. Even a controlled flare into trees at 55 knots is preferable to losing control and entering an incipient spin from 300 feet. One can live from the outcome of the first scenario...and many have died performing the latter.

Many, many of us are not around to discuss this issue because of low-altitude stall-spin accidents. These were pilots who were trained just like you and me--yet they made a critically poor decision at the worst possible moment. And you have the chance to think it through in the comfort of your own home and computer screen. Having a "plan" before this engine out scenario is critical. Flying an aircraft during that engine out situation is NOT the time to become creative in terms of aggressive turns and approaching critical AOA.

Fly the plane. Keep your airspeed under control. Accept no more than 30 degrees of bank.

It'll work!
 
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While an AOA indicator will provide guidance on the subject, i is highly unlikely that one would have the cognitive capability during this stressful time to either monitor that gauge or even listen to a warning tone.

...

Keep your airspeed under control.

Ermm... so one can't manage to monitor an AOA indicator in the pattern but one can monitor an airspeed indicator? That doesn't compute.
 
This thread brought to mind this

This discussion brought to mind this incident that happened many years ago. Several of the topics under discussion such as shoulder harness stretch, fuselage distortion, seat belt attachment practices and hitting in a flat attitude all may or do play a part. Watch this video several times and at the .55 mark you can see a secondary impact where the pilot's body moves much more that I ever thought possible. There are tremendous forces at work here. Btw the pilot survived and was one of my favorite all time airshow pilots that i've seen perform in person.

https://m.youtube.com/watch?v=BJWjbpA_zIc
 
Ermm... so one can't manage to monitor an AOA indicator in the pattern but one can monitor an airspeed indicator? That doesn't compute.

First, my statement is more likely true than the converse.

Unless one uses the AOA indicator for their primary approach reference, every day, every single approach, that pilot will very likely not have the cognitive capacity to reference all the additional indications they have normally monitor during a non-emergency approach. Most of us use airspeed as our primary (first) reference, and that's what one will gravitate to during an engine out scenario.

But, during that emergency, our capacity to incorporate extraneous data is severely limited--that's why many of us report that we get "tunnel vision" when in an extremely critical situation.

More importantly, your statement alludes to the concept that "if we can monitor AOA during that turn to a landing zone, we can turn more steeply if we monitor the AOA"

If everything worked perfectly, including your brain's capacity to both perform an unusually steep turn at low altitude, giving up that very altitude to allow for a greater AOA margin, monitoring the landing spot and your approach to it, and also monitoring the AOA meter to ensure you don't stall the aircraft, it would be do-able.

We know from experience and scientific study that the human brain simply is not capable of doing so reliably in an emergency situation.

One should not expect to perform a miracle of flight during such an event...keep it simple and keep it the safest plan possible!
 
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Not looking for an argument,

nor to steer anyone wrong. But as I read Eagle's response, I see references to steep turns and stall speed while maintaining level flight. Perhaps I wasn't clear. Nothing I said was meant to imply that one could get away without an accelerated stall while banking steeply and holding the nose up/arresting a descent. But if you let the nose settle and take the altitude loss that comes with it, you can knife-edge the plane and not stall. That's the extreme case, not something we'd ever do below 1000' AGL, but it demonstrates the point. The reason we "need" bank limits in the pattern is that we subconsciously try to force the maneuver to be a level turn - or at the least a turn without an increasing descent rate. This aerodynamics will not allow, and it will kill you if you try.

As to little warning of an impending stall, I don't find that to be true of my RV's wing or its control feel.

Full disclosure: most of the banking to 40-60 degrees I do in an overhead at my home field is done as airspeed is allowed to bleed from 160 at the perch to 65 MIAS over the fence, so little wonder I have seldom felt even a hint of incipient control mush in the last quarter turn to touchdown. Bit if I limited myself to 30 degrees, my overhead would carry me farther from the threshold than I am comfortable gliding back - or judging my energy management.

-Stormy
 
If we assume the shoulder belts are tight, it would probably take 12" or more of fuselage telescoping before the occupant's noggin struck the panel. I don't see anything like that in the photos. Without autopsy information, there is no reason to think either fuselage buckling or shoulder belt failure was a factor.

Do note that some reasonable degree of fuselage buckling is desirable. A shoulder belt anchored to a perfectly stiff structure would subject the restrained occupant to the entire g-load of the sudden stop.

Bottom line? Build to plans.

I was surprised in the fatalities from the amount of damage myself. If he belly flopped it into the road burm right behind the plane I could see them both receiving enough vertical G impact force as the gear sheared off and the plane kept going to cause internal injuries simply from the going from 60mph to 0 in about 1/10th of second.

Probably forces similar to jumping off a 10 story building strapped to a chair and landing seated upright.

It's a testament to the plane's ruggedness that it stayed in one piece with the wings still attached




beyond any of the AoA arguments the plain truth is the guy was buzzing around at 500' (probably showing off a little), got complacent and was asking for it.
Fly the numbers. Dont get cocky or complacent.
 
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