NTSB Issued Final Report for the 2019 Acclaim Ultra down at DVT

[mike_elliott]

I want to once again thank all of you who donated to the Mooney Summit, Inc. to help Jenny during Mark's trying time in the burn center. Your generous contributions enabled Marks' immediate family members to visit him, and be with him during his final hours and before.

[Shadrach]

51 minutes ago, donkaye said:

That's why I mentioned DA.  I didn't do a DA check that day as I was descending, but Chandler at 2,243' had a temperature of 102°F that day.  Standard at SL is 59°.  Assuming the standard lapse rate of 3.5°F/1000', standard at Chandler was 51°.  The temperature was 51° over standard.  A rule of thumb is DA increases 1,000' for every 15°F over standard.  That means the DA increase from standard at Chandler was 51/15 x 1,000 = 3,400' and the DA was about 5,600'.  I'm going to extrapolate and say that at 9,100' the DA was over 12,000'.

Frankly, the POH says 12,000' and doesn't quantify to DA.  So. if you wait until 12,000 to turn on the boost, it could really be above 15,000' from a DA point of view.  It's either confusing or the writers of the POH deliberately didn't take DA into account.  I'm certainly open to hear why that might be.

I'm sure it should be taken as DA as MSL altitude is irrelevant to the the fuel system. I also think that it likely that the DA at 9,000msl was well above 12,000 on the day in question.

[A64Pilot]

57 minutes ago, donkaye said:

Frankly, the POH says 12,000' and doesn't quantify to DA.  So. if you wait until 12,000 to turn on the boost, it could really be above 15,000' from a DA point of view.  It's either confusing or the writers of the POH deliberately didn't take DA into account.  I'm certainly open to hear why that might be.

Because people make mistakes possibly. I wrote the S2R H-80’s POH in its entirety, by myself. We like to think that factories have large staff’s of degreed Engineers etc., but sometimes its not what you think, the POH is FAA approved of course, and I’d assume 12,000 was considered to be a conservative number. Even if they had considered DA, it unlikely they would use it, as lazy people like me won’t compute it, more likely I think that they pick a conservative number, one the pilot had an instrument to tell him and go with that.

Does the G-1000 alert you to turn boost on at 12,000? just curious I’ve never flown one, but have flown other complex aircraft where the computer will, get into a time limited range and a timer pops up etc. That helicopter I talk about as you burned fuel, expended ordinance etc the Performance planning page updated constantly to current conditions. I would expect something as exotic as a G1000 if it threw a Master Caution, it would give you the Emergency procedure too.

[EricJ]

2 hours ago, donkaye said:

Actually, the airplane was equipped with the G1000 NXi.  I believe there is data recording with that unit, but I could be wrong.  Do you know, Mike?  Unless it was totally destroyed, you would  think the NTSB might have been able to get some engine data from it and found out the cause of the engine issue.

The fire was substantial.    I'd be very surprised if any of that survived to provide post-crash data.

[donkaye]

27 minutes ago, A64Pilot said:

Does the G-1000 alert you to turn boost on at 12,000? just curious I’ve never flown one, but have flown other complex aircraft where the computer will, get into a time limited range and a timer pops up etc. That helicopter I talk about as you burned fuel, expended ordinance etc the Performance planning page updated constantly to current conditions. I would expect something as exotic as a G1000 if it threw a Master Caution, it would give you the Emergency procedure too.

It does not automatically.  It should.  You can program in an alert for tank change.  If there was a a way to recognize the altitude in the alerts menu, then it could easily be set up.

[A64Pilot]

2 hours ago, donkaye said:

It does not automatically.  It should.  You can program in an alert for tank change.  If there was a a way to recognize the altitude in the alerts menu, then it could easily be set up.

Surely it displays altitude so it could.

I Retired before I got as much done as I wanted to, one thing I wanted was to have a switch on the control stick that you could push and have the MVP-50T pop up an artificial horizon as every now and again a crop duster will go inadvertent IMC, and if they could pop up artificial horizon it could be a life saver. Most won't spend the money or panel space on one. I did have a G meter with the MVP as the FAA was sure that Ag pilots were getting G tolerant and pulling excess G’s without knowing it. We found out that was not true by downloading several customers MVP’s

I would have thought Garmin, the company that can apparently have an airplane land itself at the push of a button would auto page emergency procedures etc, remind you gear down, maybe display before landing checklist if airspeed fell below a certain point etc. watch fuel levels and consumption and warn you when 30 min of fuel remain, remind you to switch tanks based on fuel level, ITT get above a set number, tell you to enrichen mixture, etc etc.

It’s the 21st Century with electronics if we can dream it up, it can be done. It’s astonishing at what can be done

Perhaps the follow on one will? “glass” is out of my budget so I don’t know much about most of it. I trained 40 years ago on old school round gauges and am comfortable with it.

[kortopates]

Vapor lock is real, I see it frequently in summer. Its not always possible to diagnose in the data unless the monitor includes fuel pressure. But sometimes its evident in FF data as well. Although the Ultra calls for the boost pump on starting at 12K, its an interesting comparison to the Cirrus TCM turbo which uses a near identical engine calls for the low boost pump on from takeoff throughout the climb and then the high boost pump to be used starting at 18K' and on to prevent vapor lock. You even set up the max takeoff FF with the low boost pump on. 

[carusoam]

Yikes,

That was a long wait for the accident report to be published…

 

Bummer,

No smoking gun to be found after the whole plane got burned…

 

Prayers,

Mark, you will always be remembered…

 

 

Note: the Ovation doesn’t get a FuelPressure gauge… Does the Acclaim get one, for the reasons generously posted above?

Best regards,

-a-

[hais]

15 hours ago, A64Pilot said:

Vapor lock in flight would be very unusual, I have never heard of it in a GA airplane, the reason it would be very unusual is the fuel is being used and often there is a return line as well, meaning there is constant cool fuel flowing through the lines. You usually see it after refueling on a hot day of course when you restart.

Car gas however is much more likely to vapor lock if you have an aircraft that is allowed to use it, often a continuous fuel pump may be added and or cooling ducts to parts of the fuel system etc.

For Certification the FAA requires a hot fuel test where the fuel is heated on the ground to a hot temp and then the aircraft is flown at max continuous power to its service ceiling, the purpose of the test is checking for vapor lock, the higher altitude of course due to reduced pressure reduces the temp the fuel will boil, This test came from problems WWII fighters experienced especially in the Pacific theater, Image a dark blue Corsair sitting in the sun soaking up all that heat, then flown at a phenomenal climb rate to the flight levels, they rarely experienced vapor lock, so we now test for it. Not sure which airframe I just said Corsair as they were dark blue I think.

If you ever get vapor lock you should see fluctuating fuel pressure and if you have the old style fuel flow meter that works off pressure, it will be bouncing around too, of course if you suspect vapor lock turn on the boost pump, if it’s vapor locking after the pump (most probable) that should eliminate the vapor lock.

https://www.law.cornell.edu/cfr/text/14/25.961

I’ve had to fly a few of these and ended up with a couple hundred gallons of free Avgas as the PT-6 is allowed to burn Avgas for a limited time, and you test the worst case fuel.

 

Happened to me once in an IO-240 powered Diamond C1 - at least that's what suspected because the engine ran just fine on the ground after my on-airport emergency landing.

[ilovecornfields]

2 hours ago, kortopates said:

Vapor lock is real, I see it frequently in summer. Its not always possible to diagnose in the data unless the monitor includes fuel pressure. But sometimes its evident in FF data as well. Although the Ultra calls for the boost pump on starting at 12K, its an interesting comparison to the Cirrus TCM turbo which uses a near identical engine calls for the low boost pump on from takeoff throughout the climb and then the high boost pump to be used starting at 18K' and on to prevent vapor lock. You even set up the max takeoff FF with the low boost pump on. 

This never made sense to me. Why does the IO-550 have the boost pump off for takeoff and landing but the Lycoming engines have it on? I know you can flood the engine with high boost but it just seems like low boost might be helpful during takeoff any landing and to prevent vapor lock. 

[GeeBee]

10 hours ago, ilovecornfields said:

This never made sense to me. Why does the IO-550 have the boost pump off for takeoff and landing but the Lycoming engines have it on? I know you can flood the engine with high boost but it just seems like low boost might be helpful during takeoff any landing and to prevent vapor lock. 

Different systems. The Lycoming uses a diaphragm pump which is more prone to vapor locking.

 

[GeeBee]

12 hours ago, carusoam said:

Remember…. The Ovation has the boost pump connected to the throttle.  At WOT, the boost pump is on for you…. And comes back off as power is reduced…

Hmmmm…. I have no idea if cruising with WOT has the boost pump running for hours…. 

PP thoughts only, not a mechanic…

Best regards,

-a-

You lost me there. Is that the way your Ovation is rigged?

 

[Shadrach]

3 hours ago, GeeBee said:

Different systems. The Lycoming uses a diaphragm pump which is more prone to vapor locking.

 

It never occurred to me to that Lycoming’s recommendation to operate the boost pump during take off and approach ops was vapor lock related. I always thought it was simply for redundancy during phases of flight in close proximity to the ground.  After two premature pump overhauls, I stopped using it for anything but starting. Never saw a fuel pressure fluctuation on the mechanical pump at any altitude (DA’s as high as 18,000) or temp (East coast summers). I now use the modified pump for take off and landing but the system has never seemed susceptible to vapor lock.

[GeeBee]

While both the rotor pump and the diaphragm pump create low pressure pulses, the diaphragm pump creates less of them, but they are deeper and lower than a rotor pump, hence the higher susceptibility of the diaphragm pump. Seen this on boats many times. Mercruiser even took to mounting the fuel pump off the raw water pump shaft to help keep it cool because suction and heat was causing vapor locking with carb'd engines. Even now, marine engines with fuel injection use an electric rotor pump which pulls rather than a submerged pump which pushes (like on your car) and there is sometimes vapor locking, but not like the old diaphragm pump days. They came out with an insulated fuel filter to mitigate the issue. The problem for marine engines is they all must suck fuel for safety reasons. If you notice almost all high altitude airplanes have submerged fuel pumps that push rather than suck. Often times, without a pusher pump fuel can begin "gassing out" at high altitude. Dissolved air starts bubbling out like a carbonated beverage at high altitudes. Most AFM's will tell you that you can engine suction feed fuel in the event of submerged pump failure but not reliably.

 

[GeeBee]

Just now, carusoam said:

Old fuzzy memory….

It should be described in the POH….   Now, where would I look that up…!  

Best regards,

-a-

Nothing I can see in mine, or the MM manual or the wiring diagrams......

[donkaye]

15 hours ago, carusoam said:

Remember…. The Ovation has the boost pump connected to the throttle.  At WOT, the boost pump is on for you…. And comes back off as power is reduced…

Are you sure about that?  I've never seen a boost pump light come on at full power in an Ovation.  In the Bravo the Boost Pump comes on at full power along with a light indication, in the Ovation I don't think so.

[Shadrach]

34 minutes ago, donkaye said:

Are you sure about that?  I've never seen a boost pump light come on at full power in an Ovation.  In the Bravo the Boost Pump comes on at full power along with a light indication, in the Ovation I don't think so.

I think Anthony is perhaps conflating “Boost pump” with an economiser or enrichment circuit.
IIRC, TCM engines are set up for additional fuel flow at wide-open throttle, but I’m no expert on that system.

[carusoam]

23 minutes ago, donkaye said:

Are you sure about that?  I've never seen a boost pump light come on at full power in an Ovation.  `In the Bravo the Boost Pump comes on at full power with a light indicator, in the Ovation I don't think so.

Interesting….

I can’t find any reference to it at all….

Possibly something I heard about along the way….  I’m pretty good at clearing out mixed memories…. 

It was possibly a question that came up during Transition Training…. The proper answer got lost over time…

 

Now….

How does the 310hp engine’s mechanical fuel pump keep up With the added fuel flow….?

Some IO550s use a max 25gph…. Others are closer to 30gph….

And there is no requirement to ever turn on the fuel pump for T/O…

 

 

Related to Mark’s accident…

The IO550 has a fuel line that returns fuel to the selector valve….

prior to a hot start… fuel and vapor get forced back to the tanks when the mixture is held in the Idle cut-off….

Is this return line ever active during flight? (Possible route for vapor to be separated out…)

 

Are only turbo Mooneys susceptible to vapor lock?

Is there something I may want to consider for my lower altitude IO550?

 

PP questions only, learning things from Mark’s experience…

Best regards,

-a-

[A64Pilot]

2 hours ago, Shadrach said:

It never occurred to me to that Lycoming’s recommendation to operate the boost pump during take off and approach ops was vapor lock related. I always thought it was simply for redundancy during phases of flight in close proximity to the ground.  After two premature pump overhauls, I stopped using it for anything but starting. Never saw a fuel pressure fluctuation on the mechanical pump at any altitude (DA’s as high as 18,000) or temp (East coast summers). I now use the modified pump for take off and landing but the system has never seemed susceptible to vapor lock.

It had never occurred to me either, but all the boost pump would do is pressurize the small section of fuel line between the two pumps because the mechanical pump has what’s past it under pressure already, but maybe it’s to help prevent vapor lock?

Makes one wonder.

I’ve been doing some thinking, I know dangerous, but Vapor lock is a function of two things, temp and pressure, drop pressure and you may get it, hence the boost pump on.

However if you had a restriction, say a dirty gascolator, then there would be a low pressure between the restriction and the pump, and you could get vapor lock, where you normally wouldn’t because the restriction would cause a reduction in pressure. Anything to cause a restriction would reduce pressure before the pump, and could set up vapor lock?

Edited June 1, 2022 by A64Pilot

[Shadrach]

1 hour ago, A64Pilot said:

It had never occurred to me either, but all the boost pump would do is pressurize the small section of fuel line between the two pumps because the mechanical pump has what’s past it under pressure already, but maybe it’s to help prevent vapor lock?

Makes one wonder.

I’ve been doing some thinking, I know dangerous, but Vapor lock is a function of two things, temp and pressure, drop pressure and you may get it, hence the boost pump on.

However if you had a restriction, say a dirty gascolator, then there would be a low pressure between the restriction and the pump, and you could get vapor lock, where you normally wouldn’t because the restriction would cause a reduction in pressure. Anything to cause a restriction would reduce pressure before the pump, and could set up vapor lock?

If I recall correctly the FP line goes from servo to the gauge (I'd much prefer a sender but that's a different thread). My boost pump will push pressure above what the mechanical pump is providing (~25psi) to just a hair under redline (30psi).  It's worth nothing that the pump was not this strong prior to being overhauled and modified by Aeromotors.  Anyway, the boost pump in my plane definitely boosts pressure beyond the mechanical pump to the servo.  As you said, every restriction, elbow, Tee fitting etc in a system causes a low pressure area.  Your gascolator analogy is sort of what I was referring to earlier about a failed pump temporarily creating a worse scenario than not using it at all. An immediate decrease to ambient pressure coupled with the restriction of the newly failed boost pump could make for multiple areas of cavitation aft of the mechanical pump.

[LANCECASPER]

Pure Speculation, but since the report says that he took on 58 gallons of fuel before the flight, if they topped him off and mis-fueled (Jet-A) that could mean he could have had about 50/50 Avgas/Jet-A. Or possibly even fuel contamination (water or ??). That would explain power loss, rough running engine. After the fire I doubt they could have determined what was originally in those tanks. Although I would think they would have gone back and got a copy of the receipt from the FBO. Makes me also tell myself no matter what to sump those tanks!

[EricJ]

5 hours ago, LANCECASPER said:

Pure Speculation, but since the report says that he took on 58 gallons of fuel before the flight, if they topped him off and mis-fueled (Jet-A) that could mean he could have had about 50/50 Avgas/Jet-A. Or possibly even fuel contamination (water or ??). That would explain power loss, rough running engine. After the fire I doubt they could have determined what was originally in those tanks. Although I would think they would have gone back and got a copy of the receipt from the FBO. Makes me also tell myself no matter what to sump those tanks!

Even sumping may not be fully revealing of what's in the tank.   Taking the cap off and looking and smelling, as well as looking at and smelling a sump sample gives you good coverage.

Even Bob Hoover crashed an airplane after a misfuel.   Can happen to anybody.

 

[GeeBee]

Yep, I am at the point where I not only look for water and junk, I observe evaporation to make sure its not Jet A. Too many places from the "hole" where the tanker truck dumps to the fill of the fueling truck that services your plane where things can go wrong. Especially post Covid, where labor is mostly new and inexperienced. Nice thing about the GATs jar is you can observe the evaporation on the separator screen and determine Jet pretty quickly. 

[Fly Boomer]

13 hours ago, LANCECASPER said:

Makes me also tell myself no matter what to sump those tanks!

And pump my own gas.  Doesn't help  if the FBO has contaminated fuel in their tank, but you do what you can.

[tgardnerh]

Nice thing about the GATs jar is you can observe the evaporation on the separator screen and determine Jet pretty quickly. 

Have you tested that with intentionally contaminated fuel?
I'm always a little concerned that I won't be able to tell the difference in a gats jar, so I wet a paper napkin with fuel and look for an oily spot once it dries.


Sent from my iPhone using Tapatalk