Scary VMC roll video, question for multi-pilots

[Henning]

I would not consider a 421 a light twin. I am not familiar with that particular equipment. Do they use FTD's for the 421 or sims. I have only one experience of "reprogramming" for different models and it was not positive. In SimCom the Cheyenne III training used a Cheyenne I/II and reconfigures it for the Cheyenne III. Was not impressed at all. The actual Cheyenne III sim that FS had at Lakeland (now owned by SimCom) was very superior.
Years ago I did recurrent Navajo at RTC. They used a FTD and I never went back. Just was not what I was looking for. Any training is useful, sim or FTD. JMO

The one FSI was using was a full on sim. The low end numbers one uses for all the Twin Cessnas are the same as are the handling characteristics. The cockpit layout isn't the same obviously, but that isn't a big deal for this type of training since the controls are where they belong.

 

[cirrusmx]

throttles to idle and brake!! there was a ton of usuable runway!

 

[SinkorSwim]

RedBird is capable or B58...

 

[Henning]

throttles to idle and brake!! there was a ton of usuable runway!

Not for that profile, when you rotate 5kts below red line and yank it off the ground with a high AoA, you have little to no chance. Multis require discipline to do things correctly and by the numbers. Most likely his hand was on the gear lever when the engine died.

 

[ronnieh]

What Henning said. The first 60 seconds and the last 5 minutes of flight in a twin, especially light twins must be flown correctly. It does take discipline and practice. What that pilot did was just plain stupid. You can't fix stupid.

 

[dtuuri]

I was watching this excellent video from an FAA accident investigator covering what he thinks are the ten most common causes of GA accidents.

The accident that really took me back was at 28:13 into the presentation:

http://youtu.be/Zr6iLRIN234?t=28m13s

This is a reconstruction of a vmc roll in a turboprop twin right after liftoff. I'm looking at this trying to figure out what the accident pilot did wrong. The roll happened so fast I don't think I could have reacted fast enough to counter it either.

I wonder if that's an exact reconstruction of a specific accident or a loosely-made one of this similar accident:

http://www.airdisaster.com/reports/ntsb/AAR80-08.pdf​

In the linked accident, the pilot had very little experience in the PA-31. The engine started surging earlier than lift-off speed, according to witnesses, affording ample time to abort on a very long runway had the pilot done so.

It's hard to imagine any professional multi pilot lifting off below Vmc, even with low time in type. It's not hard to imagine being too timid in reacting to the power loss adequately with little experience in type.

I've experienced the fuel selector lever pop out of the detent right after lift-off on a PA-31P, the same airframe as the Cheyenne's. If that happened to the Comair Navajo too, it conceivably could cause the surging engine noise heard by the witnesses, not to mention distracting the pilot from making a prudent abort decision. The NTSB felt the right engine's fuel supply could have been interrupted by the rolling takeoff from a left turn onto the runway, unporting the fuel line from the tank. A surging engine may have led the pilot to believe the cause was a simple management problem he could correct, losing control in the process.

On another note, I want to say a word about the blue line. It's an emergency quick-reference speed for takeoff only. It doesn't apply to landing approaches. Not only that, it isn't even an optimum performance speed for most takeoffs. Virtually all the variables that go into establishing the published speed make it higher than the optimum speed for most situations. You could say it's a maximum target speed for optimum performance, not a minimum. In contrast, Vmc is a minimum target speed, since any speed above that will at least allow control if not climb performance.

dtuuri

 

[Henning]

I wonder if that's an exact reconstruction of a specific accident or a loosely-made one of this similar accident:

According to the FAA guy it was an exact.

 

[poadeleted20]

Feathering lowers the Vmc speed. My plane has a Vmc of 128 windmilling and 100 feathered. I rotate at 106 so an AutoFeather system is required.

That said, because the unfeathered Vmc is 128, that's where the regulations require the red line be placed.

 

[dtuuri]

That said, because the unfeathered Vmc is 128, that's where the regulations require the red line be placed.

It's been a looong time, but IIRC the NTS (negative torque sensing system) system on MU-2s, Turbo Commanders, etc., was 'almost' an auto-feathering system, but the red line was based on an operational NTS system not a failed one.

dtuuri

 

[TangoWhiskey]

They are computed for a specified set of conditions, some of which are worst case (e.g., aft-most cg), some of which are arbitrary (e.g., 5 degrees bank into the good engine). Bank angle is the one which is probably least understood, although the article by the late Prof. Mel Byington is probably the best discussion about that.

https://www.aopa.org/Pilot-Resource...ne-Out-Booby-Traps-for-Light-Twin-Pilots.aspx

Ron, do you have a link to a copy of that article WITH the figures he refers to? The AOPA version is missing the referenced graphics/charts.

 

[j1b3h0]

Turboprop pilots needn't worry so much about engine failures: It's the prop that will kill you; or, rather the thrust asymmetry caused by one running hard and one unfeathered. If, for some reason the prop can't be feathered, it's good night Irene!...even from cruise flight. A Brasilia crash or two springs to mind.
A real eye opener in the Saab 340 simulator was a engine failure/auto coarsen scenario. If the pilot was really on his game, he'd be luck to not scrape the trees.

 

[Captain]

Lift vector is up and weight vector is down. With one engine inop the remaining engines thrust vector yaws the aircraft and the rudder counters this. So...you end up in a slip with wings level and one engine caged.

Bank takes a bit of lift vector and applies it horizontally to counter the yaw induced by the off centerline good engine. They limit MANUFACTURERS to 5 degrees to certify their aircraft because otherwise they could show a super low Vmc but with 60 degrees of bank. That's not fair and the FAA caps them at 5 degrees.

A pilot, however, can use whatever he can to keep the plane flying straight. Also, reducing power on the good engine may be the ticket if starting to roll below Vmc rather than just slamming it shut as some have suggested. Maybe reducing to half power would be enough to milk it over some buildings to make the field on the other side? Point is, Vmc goes WAY down when you reduce power, even by half.

 

[Jimmy cooper]

The two high time multi engine pilots I've flown with in the following, turbo commanders, mu2 stretch, and super star both have the gear coming up the instant it breaks ground. I mean like right now. One of these pals checked me out in a mooney 201-super 21 years ago. Same deal with the gear. Both agreed on multi engine takeoff failure, not a big problem in any of the above IF you don't come unglued and fly it by the book. One of them flew a standard aerostar, unpressurized, out of 2200 feet, 0w3, repeatedly. Both had well over 12000 hours at this time. One retired with 16000 hours, the other still flying a superstar has 14000 .

 

[Fearless Tower]

The two high time multi engine pilots I've flown with in the following, turbo commanders, mu2 stretch, and super star both have the gear coming up the instant it breaks ground. I mean like right now. One of these pals checked me out in a mooney 201-super 21 years ago. Same deal with the gear. Both agreed on multi engine takeoff failure, not a big problem in any of the above IF you don't come unglued and fly it by the book. One of them flew a standard aerostar, unpressurized, out of 2200 feet, 0w3, repeatedly. Both had well over 12000 hours at this time. One retired with 16000 hours, the other still flying a superstar has 14000 .

There are also plenty of 30,000 plus hour ME pilots that don't do that.

I don't see that much to be gained by pulling the gear up as soon as the wheels break ground. You may accelerate to blue line a smidge faster, but how much are you really gaining? Remember, in most GA twins, engine failure before reaching blue line means abort. By bringing the gear up so soon, you are essentially committing yourself to go during a very marginal period (between red and blue line) where even if you react with near perfection, the airplane may not be able to fly out in many conditions. Kind of nice to have the gear down if that happens and if you do lose it before blue line and you have the gear down, you have the advantage of a slight decrease in VMC.

Now, as with most things in life, there are always exceptions, but the B-25 is a very different animal from most piston GA twins.

 

[Henning]

There are also plenty of 30,000 plus hour ME pilots that don't do that.

I don't see that much to be gained by pulling the gear up as soon as the wheels break ground. You may accelerate to blue line a smidge faster, but how much are you really gaining? Remember, in most GA twins, engine failure before reaching blue line means abort. By bringing the gear up so soon, you are essentially committing yourself to go during a very marginal period (between red and blue line) where even if you react with near perfection, the airplane may not be able to fly out in many conditions. Kind of nice to have the gear down if that happens and if you do lose it before blue line and you have the gear down, you have the advantage of a slight decrease in VMC.

Now, as with most things in life, there are always exceptions, but the B-25 is a very different animal from most piston GA twins.

Only if you use poor "save the plane" logic. If you don't have qualms with setting the plane on the belly, there's no difference in options. Personally I'm "Positive rate, gear up" unless I'm on a really long runway, then I still have it up by 50'.

 

[Fearless Tower]

Only if you use poor "save the plane" logic. If you don't have qualms with setting the plane on the belly, there's no difference in options. Personally I'm "Positive rate, gear up" unless I'm on a really long runway, then I still have it up by 50'.

Maybe, but even if you are willing to sacrifice the airplane, what are you really gaining by pulling the gear up so soon? With the exception of the B-25 and maybe the DC-3, in every twin I have flown, by the time I have true 'positive rate', I am at blue line.

 

[Henning]

Maybe, but even if you are willing to sacrifice the airplane, what are you really gaining by pulling the gear up so soon? With the exception of the B-25 and maybe the DC-3, in every twin I have flown, by the time I have true 'positive rate', I am at blue line.

More performance if I take the option to keep going. Every take off is its own. Even if I'm going into the trees, I'll take the tops over the trunks.

 

[Jimmy cooper]

They felt, on a twin , if an engine got a hair in its throat or if they lost an engine, they didn't want the drag and they didn't want to screw with the gear while trying to fly the airplane. Seems pretty elementary to me. It certainly worked for them . In one instance, Lancaster penna. On takeoff, immed. IFR, right engine quit in aerostar. Pilot, 3 passengers, brought it back in to same airport with no trouble.

 

[bbchien]

They felt, on a twin , if an engine got a hair in its throat or if they lost an engine, they didn't want the drag and they didn't want to screw with the gear while trying to fly the airplane. Seems pretty elementary to me. It certainly worked for them . In one instance, Lancaster penna. On takeoff, immed. IFR, right engine quit in aerostar. Pilot, 3 passengers, brought it back in to same airport with no trouble.

Feel Schmiel. Then these guys are not computing V1.

Fail between V1 and V2, means you reject the takeoff. Sucking up the gear early just means you are more than hands full if you don't make V2.

It's not ready to fly until you have accomplished the number. And on neither of those a/c does it want to stay on the ground until V2.

 

[ChitDisturber]

F'ing MS flight sim videos.....

 

[Captain]

Wtf is V2?

V1 is decision speed so how would you abort after the decision? I'm lost.

 

[RotorAndWing]

Wtf is V2?

.

Takeoff safety speed. The speed at which the aircraft may safely become airborne with one engine inoperative

 

[Captain]

Well I've never heard of rejecting the takeoff after V1. Seems to defeat the point.

 

[dtuuri]

Well I've never heard of rejecting the takeoff after V1. Seems to defeat the point.

Yes. With all due respect to Dr. Bruce, I don't like to mix metaphors. Light twins don't have V1 & V2 speeds, which are calculated scientifically by the manufacturer for the gross weight and density altitude of each takeoff.

That said, I employed a poor-man's "balanced field" concept to light twins myself that doesn't require the confusing use of those terms. I would add the multiengine takeoff distance to the multiengine landing distance and then add a safety factor. Then, I tried to stay out of places tighter than that. My 'decision speed' came while airborne, unlike V1, at 50' AGL. From that point, above most typical obstructions and with some open space remaining ahead, any decision to continue after an engine failure was much more viable. Maintaining level flight while already clear of most of the obstructions or even descending slightly, instead of trying to climb or fixating on achieving blue line, became my modest objective of any 'go' decision. Any climb after cleaning the airframe would be a happy bonus. I would tie the decision to 'continue' to gear retraction--never lower than 50' AGL. If I needed to abort, I reasoned my pre-computed balanced field was based on maximum braking. If I decided to continue, the gear would be in transit already when the engine failed, saving valuable time.

dtuuri

 

[ronnieh]

First a comment on Jim's high time pilots. It is tricks like this that led to the SFAR for the MU2. It is well known that sucking the gear up like this on the MU2 is just wrong. The MU2 has a relatively long gear cycle time. During the retract phase the drag increases significantly, much more than with gear just extended. In the MU2, the pilot is taught to leave the gear down until you have a little altitude. There are many configurations where the MU2 will have a negative climb on one engine while gear is in cycle. In most situations you will have zero climb while the gear is cycling. Ten feet above the runway is not where you want to get into a negative climb situation.
DTUURI has it correct. Dr. Bruce has chosen to go a step further and do some flight testing to come up with some numbers for his particular plane. He has chosen to call these numbers V1 and V2. But as was mentioned they do not exist for the planes we are discussing. In very broad terms the speeds are reserved for turbojet aircraft. I suspect some large transport prop planes may also have this info. V1 and V2 has to be calculated for each take off. You can Google V1 and V2 for a more complete discussion of these speeds.

 

[Captain]

That said, because the unfeathered Vmc is 128, that's where the regulations require the red line be placed.

Sorry, the red line is at 100 kts...the feathered Vmc speed. I didn't post before because I wanted to make sure. Looked at it today and right there at 100 kts is the red line. Piaggio uses the feathered Vmc number.

 

[denverpilot]

Another small point. Doc flew a number of things that had computed V1 and V2 prior to his light twin days.

The law of primacy in action, his decision to keep calling them by familiar if somewhat inaccurate terms. Heh. Even happens to high time CFIs.

Interesting also that I could figure that out and yet a much higher time pilot with multi experience had to pick the nit. Heh. Not saying it's bad to do so. Just chuckling at y'all. This dummy knew what he meant from multiple previous posts on the matter.

I've even learned how he makes approaches into places like Aspen a hell of a lot safer by calculating a new missed approach point that is at an altitude where HIS airplane can still climb out and back to the published safe altitudes up there. Made me think about numbers for that in my doggy 182.

Bottom line and you pros know this but for the newer folks surprised by all these numbers and performance issues and what-not in light twins... Pros fly by the performance numbers. The more of that non-pros can put into their flying the better.

I have the oddball background of having attended a school that was teaching future pros and everything was spoken of in performance numbers, attaining fhose numbers, etc. Then ending up flying for "fun" instead of work. I'm always appalled when I run into pilots flying for decades who ask questions that their POH numbers can answer. And they haven't cracked a POH in years. Or done a TOLD sheet or equivalent. (Takeoff and landing data. You calculate your exact takeoff distance and landing distance for your expected DA before you get in the airplane.)

Yeah I know for a bump around the pattern at your home airport on a normal temperature day you know where about you're going to lift off and how much distance you need to stop in. But go to another airport. Did you calculate it or are you guessing? Ok I'm guilty of not doing it too.

But in a light twin the ante is raised. You need to be a "knowin' man" versus a "thinkin' man" as one old guy used to tell me whenever I said, "I think that..."

Multis have a few more ways to bite you square in the butt. Vmc roll over is but one of them.

 

[ronnieh]

Denver, not sure who you thought was picking a nit. Dr. Bruce could be confusing to some people. It took me a couple of seconds. Aircraft that do have a V1 speed, do not reject a take off after V1. That is after all the point of the speed.
Dr. Bruce was specifically talking about his generated "V1" or perhaps the correct term is pseudo V1. Some may have looked up the term V1 and have a hard time trying to figure out what Dr. Bruce was talking about. Those of us familiar with the testing he did with his Seneca II understood he was not talking about planes with actual V1 speeds. Just clarifying.

 

[bbchien]

Yes. With all due respect to Dr. Bruce, I don't like to mix metaphors. Light twins don't have V1 & V2 speeds, which are calculated scientifically by the manufacturer for the gross weight and density altitude of each takeoff.

That said, I employed a poor-man's "balanced field" concept to light twins myself that doesn't require the confusing use of those terms. I would add the multiengine takeoff distance to the multiengine landing distance and then add a safety factor. Then, I tried to stay out of places tighter than that. My 'decision speed' came while airborne, unlike V1, at 50' AGL. From that point, above most typical obstructions and with some open space remaining ahead, any decision to continue after an engine failure was much more viable. Maintaining level flight while already clear of most of the obstructions or even descending slightly, instead of trying to climb or fixating on achieving blue line, became my modest objective of any 'go' decision. Any climb after cleaning the airframe would be a happy bonus. I would tie the decision to 'continue' to gear retraction--never lower than 50' AGL. If I needed to abort, I reasoned my pre-computed balanced field was based on maximum braking. If I decided to continue, the gear would be in transit already when the engine failed, saving valuable time.

dtuuri

Dave, they sure do have a V1 and V2, They just don't publish the table.....not required to. And many pilots don't understand that V1 varies with "today's conditions".

If you have gumption, and a family you are trying to protect, you do the work and get values in a variety of temps, baros, loads, and winds.

The key here is that most light twin pilots are not equipped with the tools to rationally plan their actions prior to throttle push. We need to be supplying the tools.....

 

[dtuuri]

Dave, they sure do have a V1 and V2, They just don't publish the table.....not required to. And many pilots don't understand that V1 varies with "today's conditions".

If you have gumption, and a family you are trying to protect, you do the work and get values in a variety of temps, baros, loads, and winds.

The key here is that most light twin pilots are not equipped with the tools to rationally plan their actions prior to throttle push. We need to be supplying the tools.....

Ok Doc, please enlighten the masses then. My way is super easy and based on published data, but it isn't the only way. Perhaps you've posted your method here before, in which case just a link will do.

Btw, I think this is a great conversation to continue for the benefit of future (and current) MEI pilots. I'm not against homemade standard operating procedures for light twins, just the confusing use of terminology. You know I'm right about that. Er, don't ya? That term (V1) is defined in FARs and the speed must be attained while still on the ground, by rule. That means it can be limited by Vmcg (minimum control speed-ground), which requires testing. Vmcg can be higher than Vmca, so planning to lift off below it, based on an under-rigorous calculation of V1 could be fatal. Just sayin'...

The Cessna 310, IIRC, had a published speed of 105 MPH that could be likened to V1. The trouble was, if you lost an engine there it took ridiculously more runway to clear a 50' obstacle than to stop. I just don't see a practical way to figure how much to raise that speed to balance the stopping distance with the going distance, which is the purpose of V1. Even if there was a way, I'm pretty sure the result would be much higher than I'd want to go before rotation on every takeoff.

dtuuri

 

[Vf6cruiser]

A+ pilots actually are safer in twins......as in Hoover.......... C- pilots that think twins are cool and have them because they can afford them will soon find they have just MULTI-plied their chances of spiraling into the dirt.

 

[Captain]

Cap'n Ron,

Your post got me curious so I went and did a little more research and found this:

14 CFR 23 Criteria for Establishing Vmc
Under 14 CFR Part 23 small airplane certification rules, the specific set of circumstances required to determine Vmc are as follows:
• Maximum available takeoff power
• Propeller windmilling in takeoff pitch (or feathered, if equipped with
autofeather)
• Most unfavorable (aft-most) center of gravity and maximum takeoff
weight (or any lesser weight necessary to show Vmc)
• Landing gear retracted
• Wing and cowl flaps in the takeoff position
• Trimmed for takeoff
• Airborne, out of ground effect.
Under these conditions, the flight test pilot must be able to:
1. Stop the turn that results when the critical engine is suddenly made inoperative within 20 degrees of the original heading, using maximum rudder deflection and a maximum of five degrees angle of bank into the operative engine; and
2. Thereafter, maintain straight flight with not more than a five degree angle of bank.

Notice bullet point number two. "Windmilling (or feathered if equipped with auto feather system)"

So, I'm thinking they can put the red line at 100 based on that. Remember, 100 is feathered Vmc and 128 is windmilling Vmc. Agree?

 

[bbchien]

Dave, just like any other large a/c, V1 for a piston twin is best understood as the airspeed on a day, TODAY, that will result, after a 3 second hesitation and throttle cut, in the nosewheel still being on the pavement and not protruding through the fence, as in this pic.

The climb capability of Light twins is so marginal that to take any other speed than Vyse for V2 is just insane.

When I brought the Seneca to town, it was a double runout. I accumulated about 800 points on a spreadsheet, weights, winds, baros, temps, and created a go /stop and a kill/go grid that for obvious reasons I will NOT share. I've discussed it at least 5 years ago and since.

I really need 5500 on a summer day a gross for V1=Vyse. shorter than that if I have made Vyse when it quits, it's trees vs nurse it around......

 

[TMetzinger]

The answer is be ready to slam the throttles shut at the first hint of a yaw...at least until the point when landing straight ahead is less surviveable than flying it around and bringing it back.

THIS. I want to make contact with the ground in a level configuration under control. Having the gear down would be nice. On a runway even better. With adequate distance to stop? Sweet. But I give up those things in that order, in reverse... I NEVER give up control of the airplane.

 

[ronnieh]

Now I am confused. V1 = Vyse? Would you not be airborn well before Vyse? V1 has to be a speed while still on the ground at which you can (must) continue the TO. I know balanced field has to be taken into consideration. For this I am assuming enough runway to abort at V1 and stop. I am sure I am not understanding what Bruce is saying. I fully understand wanting data points on what the plane can do under different scenarios. I am having difficulty understanding V1 in a light twin.

Then secondly V2 has to be Vyse? So V1 and V2 are equal to Vyse? Obviously I am easy confused, a little help.

 

[dtuuri]

Dave, just like any other large a/c, V1 for a piston twin is best understood as the airspeed on a day, TODAY, that will result, after a 3 second hesitation and throttle cut, in the nosewheel still being on the pavement and not protruding through the fence, as in this pic.

I've been raking leaves all day and trying to solve the riddle of what your method actually is. The time really passed quickly, but I never did get it! A V1 speed is the speed that matches the "go" distance with the "stop" distance under the given conditions of weight, configuration, density altitude, runway contamination, etc. It's a 'speed of indifference' with regard to engine failure, since the pilot is happy either way--go or stop. In your method, are you saying you have worked out such a speed, i.e., one that results in a balanced field? If it can be done, I'm sure you're the guy who can do it, but I'd like to know how.

The climb capability of Light twins is so marginal that to take any other speed than Vyse for V2 is just insane.

Well, Vyse is too fast for a dirty airframe. As long as you're above Vxse you're in a better position climb angle-wise by being below blue line. If you've got a speed that you know will hold altitude while you clean up, then by the time you're done I bet you're pretty close to blue line without having to spend much time stressing about it. Eventually, though, what you say is true. After all, that's why they paint it bright blue isn't it?

When I brought the Seneca to town, it was a double runout. I accumulated about 800 points on a spreadsheet, weights, winds, baros, temps, and created a go /stop and a kill/go grid that for obvious reasons I will NOT share. I've discussed it at least 5 years ago and since.

I searched a little, but didn't see any grids. Only saw a post in 2011.

I really need 5500 on a summer day a gross for V1=Vyse. shorter than that if I have made Vyse when it quits, it's trees vs nurse it around......

I'm afraid I just don't know what you mean, Bruce. Sorry. I'm sure there's good info there for multi pilots to consider, but if they're like me they might be scratching their heads too. You aren't saying you advocate holding the plane on the ground 'till blue line, are you? If so, I think Vyse in the P-Navajo I once flew was something like 133 MPH. Not sure it could even unstick at that speed.

Please, more info, this is good stuff to discuss.

Dave

 

[ronnieh]

dtuuri, Bruce said he would not share the data. Like I said in the post just prior to yours, I am also confused. I will back out and perhaps you can figure it out from Bruce. Then explain it to us, the easily confused.

 

[Jimmy cooper]

If you look at the gear on a stretch MU2, it's hard to imagine how the gear coming up would slow the airplane down. Regardless, that's how these two pilots worked the airplane and flew them for many many hours. Once they knew it was airborne, the gear came up. There are many high time pilots who had disastrous experiences with MU2's so I think these two were pretty knowledgeable about what they flew. The MU2 has lotsa power.

 

[ronnieh]

Jimmy, the phenomenon of the MU2 gear has been well known in the MU2 community for quite some time. The SFAR 108 has been in affect for several years. The curriculum is mandated by the SFAR. This procedure is in the curriculum in the SFAR. The curriculum is very detailed and quite extensive. Twenty hours ground and 12 flight hours for initial and eight and six for recurrent are mandated. Appendix D gives the curriculum.
I have a good friend that flys a long body MU2 and he has over 1000 hours in the past 4 years. He is also an A&P and has showed me on the gear why this is so. So I have looked at the gear.
If you don't fly an MU2 then it is of no concern. If you do fly one you will be subject to the SFAR and you will be taught the correct way. Simple as that. Many high time pilots fly aircraft incorrectly. The MU2 is a little less forgiving of sloppy or incorrect flying. Please feel free to look up the SFAR.
Back to your regular scheduled programming.

 

[Henning]

dtuuri, Bruce said he would not share the data. Like I said in the post just prior to yours, I am also confused. I will back out and perhaps you can figure it out from Bruce. Then explain it to us, the easily confused.

Bruce is liability averse, if he publishes that data and someone uses it in their Seneca and crashes, he becomes part of the lawsuit.