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

[GeeBee]

15 minutes ago, tgardnerh said:

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.


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Yes, I have. It is readily apparent.

 

[EricJ]

The smells are completely different, too.    Jet A stinks, avgas has that sweetish smell.   Even a blend of the two will smell very different if you are expecting avgas.

 

[A64Pilot]

I believe the nozzle now is different and the Jet-A nozzle won’t fit into a pistons fuel opening.

See the big flat end, https://www.gammontechstore.com/ProductDetails.asp?ProductCode=OPW-295SAJ0200

Jet-A is extremely low Octane, something like 30, it will start detonating almost as soon as an airplane gets much of it, if it had been Jet-A there should have been some damage, and if there was any fuel left to check they would have, because an airplane having engine problems seven minutes after departure when refueled really screams fuel contamination.

But you do have to watch line men, I was over at the FBO in Albany Ga with an R-1340 crop duster and asked for fuel, we were standing in front of the airplane and the kid said, Jet right, these things use Jet don’t they? How could you miss that big 9 cyl radial? At least he asked.

Edited June 2, 2022 by A64Pilot

[GeeBee]

Nozzles, have been compromised. There was the case of the Aerostar where the lineman tilted a Jet A nozzle with a low flow rate and got the fuel in the airplane. Pilot killed.

Then there was the case in Punta Gorda, FL where the lineman put DEF fluid in the Jet A truck. It caused a Citation to dead stick into SAV. 

https://www.ainonline.com/aviation-news/business-aviation/2019-05-27/def-contamination-downs-two-citations

Lots of ways for fueling to go wrong and not all of them are entirely in your control. As Cathay Pacific 780 found out.

https://en.wikipedia.org/wiki/Cathay_Pacific_Flight_780

[AdventureD]

On 5/31/2022 at 4:59 AM, 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.

 

What?  I fly a Lancair with a big bore continental (like the Ovation and Acclaim), and vapor lock is a big deal in these engines.  On hot days, we keep low boost on down low to prevent cavitation.  Above 10,000, we keep low boost on it it is remotely hot.  Why?  vapor lock.

[AdventureD]

On 5/31/2022 at 5:41 PM, 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. 

From the Lancair community (same engines as Ovation and Aclaim), vapor lock is ABSOLUTLY REAL.  Use your boost pump to avoid cavitation when it's hot.  

I have a Bravo and a Lancair.  My understanding is that the Continental in my Lancair is more susceptible to vapor lock (quite a bit more--I dont knw why) than the Lycoming in my Bravo.  The IO 550 (Ovation) and TSIO 550 (Acclaim) folks flying Lancairs with these engines are all TAUGHT in recurrent training to use the boost pump above FL100.  It's in my ES POH.  I have little doubt what happened here.

[AdventureD]

On 5/31/2022 at 8:36 PM, 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. 

In my Lancair, my personal decision is to take off with low boost (I have high and low) on. Backup in case the engine driven pump fails; helps prevent vapor lock.  I'll turn it off in climb, but I wouldn't if it were really hot.  I'll leave it off above 10,000, but I wouldn't if it were hot, and it's the first thing I'd hit (along with richening the mixture) if the engine sputtered. 

I realize this is a Mooney forum, but we're running the same engines, and they don't operate differently based on the name on the plane.

[AdventureD]

On 6/1/2022 at 12:33 PM, carusoam said:

 

 

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-

The io 550 is definitely susceptible to vapor lock (not overly so, but in the Lancair community it's a real awareness point)

[AdventureD]

One more and I'll stop.  The original Lancairs has 3/8 inch fuel lines.  They work fine if there are not excessive bends in the lines, which disrupt flow.  But if there are significant bends, the susceptibility to vapor lock is greater.  Later versions of these planes increased the fuel line size to 1/2 inch.  Cirrus ( which largely copied the Lancair ES), has gone to 5/8 inch lines!

There is little doubt this evolution in fuel line diameter is driven by the risk of vapor lock.

I don't know the fuel line size in the Ovation and Acclaim, which use the same engines as the Lancairs and Cirrus.  But the evolution I just described in all likelihood is driven by vapor lock concerns.

[aviatoreb]

10 hours ago, AdventureD said:

What?  I fly a Lancair with a big bore continental (like the Ovation and Acclaim), and vapor lock is a big deal in these engines.  On hot days, we keep low boost on down low to prevent cavitation.  Above 10,000, we keep low boost on it it is remotely hot.  Why?  vapor lock.

Thats very interesting.

I wonder why this is not a thing in our big bore Mooneys?

[Dan OBrien]

1 hour ago, aviatoreb said:

Thats very interesting.

I wonder why this is not a thing in our big bore Mooneys?

This is one area in which the experimental side has an advantage over normally certified.  The Lancair community is well aware of the issue, and we don't need a regulation for us talking amongst ourselves to figure out that vapor lock is in issue in the IO and TSIO 550s.  We turn our low boost pumps on above 10,000 feet, or at least we have a heightened sense of awareness of the potential issue, which we would address immediately the engine gurgles.  For a commercial and normally certified operator to issue this advice would require mountains of business consideration and FAA paperwork.

My Bravo has one boost pump.  Do the Ovation and Acclaims have both a high and low boost?  We use low boost in the Lancairs to address the issue because high boost would flood the engine.

[kortopates]

23 minutes ago, Dan OBrien said:

Do the Ovation and Acclaims have both a high and low boost?  We use low boost in the Lancairs to address the issue because high boost would flood the engine.

Yes, two switches to one pump, run at different voltages for low or high. Its a Continental setup.

[Dan OBrien]

3 hours ago, kortopates said:

Yes, two switches to one pump, run at different voltages for low or high. Its a Continental setup.

Seems like the outcome of this discussion is to be aware of the vapor lock issue and prepared to hit low boost when it may be happening (or have low boost on in hot conditions to prevent it in the first place).  The high/low boost set up allows the same thing the Lancair folks do.

[carusoam]

Welcome aboard Dan!

Welcome again (professor) AdventureD,

Thank you all for your input on this important topic.

 

Lets see if we can find the diameter of M20R and TN’s fuel lines… (question for @M20Doc)

Thanks again,

-a-

[kevinw]

Given the information above, does anyone here flying a Ovation use low boost pump on takeoff? I do not (per the POH) but after reading this thread perhaps I should on hot days.

[carusoam]

6 minutes ago, kevinw said:

Given the information above, does anyone here flying a Ovation use low boost pump on takeoff? I do not (per the POH) but after reading this thread perhaps I should on hot days.

I was under the impression that the electric fuel pump was turned on automatically…

But haven’t seen a solid reference…

It was a detail covered in transition training… more than a decade ago…

The really interesting issue… My O1 didn’t get a fuelP sensor… fuel flow only…

Best regards,

-a-

[kortopates]

2 minutes ago, carusoam said:

I was under the impression that the electric fuel pump was turned on automatically…

But haven’t seen a solid reference…

It was a detail covered in transition training… more than a decade ago…

The really interesting issue… My O1 didn’t get a fuelP sensor… fuel flow only…

Best regards,

-a-

The Bravo Lycoming engine fuel pump is turned on automatically at full throttle - but not any Continental installation.

[carusoam]

For comparison…

Ovation POH for T/O and climbing….

In reverse order…

 

[Guest]

On 6/1/2022 at 6:33 PM, 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!

And be present for the refueling, or do it yourself.

 Clarence 

 

[Guest]

On 6/2/2022 at 11:46 AM, A64Pilot said:

I believe the nozzle now is different and the Jet-A nozzle won’t fit into a pistons fuel opening.

See the big flat end, https://www.gammontechstore.com/ProductDetails.asp?ProductCode=OPW-295SAJ0200

Jet-A is extremely low Octane, something like 30, it will start detonating almost as soon as an airplane gets much of it, if it had been Jet-A there should have been some damage, and if there was any fuel left to check they would have, because an airplane having engine problems seven minutes after departure when refueled really screams fuel contamination.

But you do have to watch line men, I was over at the FBO in Albany Ga with an R-1340 crop duster and asked for fuel, we were standing in front of the airplane and the kid said, Jet right, these things use Jet don’t they? How could you miss that big 9 cyl radial? At least he asked.

We lost a Navajo years ago, when the line guy couldn’t get the square Jet A nozzle into the filler, so he replaced it with a round nozzle and topped it up with Jet A.

It proves that where there’s a will there’s a way.

Clarence

 

[Guest]

3 hours ago, carusoam said:

Welcome aboard Dan!

Welcome again (professor) AdventureD,

Thank you all for your input on this important topic.

 

Lets see if we can find the diameter of M20R and TN’s fuel lines… (question for @M20Doc)

Thanks again,

-a-

Dash 6 or 3/8” supply line to the engine pump inlet fitting on an Ovation and dash 8 or 1/2” on an Acclaim from the IPC.

 Clarence 

[AdventureD]

On 6/22/2022 at 12:40 PM, 1980Mooney said:

The Ultra POH says in about 4 places to use the LOW Boost "ON for vapor suppression above 12,000 ft. or if TIT is above 1450 F degrees."   Also  "LOW Boost ON above 18,000 ft"   Additionally it states in multiple places Fluctuating Fuel Flow is likely caused by Fuel Vapor and for Suppression LOW Boost Pump is ON.  

Also 

"The BOOST PUMP (Low Boost) switch operates the fuel boost pump on low power to provide a

means of suppressing fuel vapor from fuel system during hot day and high altitude conditions.

Low boost may also be used as an engine starting aid. Continuous operation of the low boost is

permitted. "

 

It's in the Ultra Acclaim POH so this comment seems irrelevant.

Thanks for the clarification that the Acclaim Ultra covers all the bases we’ve discussed.  Agree the comment is irrelevant given the info in the POH.

[Will.iam]

So why doesn’t the TSIO-360 not have this boost pump requirement? Is it because the fuel flow demand is lower and as such doesn’t cause vapor lock?

[Dan OBrien]

Looking back on this accident, having experienced vapor lock myself twice in 270 hours in my IO-550 Lancair ES over the last year and a half, and observing the number of these incidents reported on the COPA list in IO-550s and TSIO-550s, I hope the Ovation and Acclaim folks are using their boost pumps wisely.

Happy and safe flying,

Dan

[donkaye]

I've done a number of Acclaim Ultra transition trainings since that accident.  I spend a significant amount of time discussing the use of the low boost pump.  While the cause of that accident does not blame the use of the boost pump, I still have my suspicions.

The last training I did involved picking up the plane in Chandler, flying to Scottsdale, and then coming back to Hayward.  I had it planned such that we would leave Scottsdale before the temperature got near 100°F.   Issues with the plane in Scottsdale precluded leaving before the temperature had risen to 109° and rising.  Although I've taken off from Chandler at temperatures around 102°F in my airplane with its TIO540AF1B Lycoming engine, I didn't want to take a chance with the Continental engine of the Acclaim Ultra.  We stayed overnight in Scottsdale and left at crack of dawn with the tower opened and temperatures were much lower.   Our flight back was uneventful.