Fuel pressure and flow fluctuations

Joe Larussa · August 28, 2015

Hi Mooney Drivers,

I have a 77 201 with firewall forward with 30 hours. At higher altitudes I'm seeing my fuel pressure on stock gauge oscillate from 25-21 and fuel flow jump from 10.3 to 9.7-ish. All is good on climb and solid on descent. Altitude wise I'm talking 10-11k. Soon as you hit the boost goes right to 26. Thoughts?

**jetdriven** · August 28, 2015

i insulated my fuel line from the firewall to the pump and it calmed down the fuel pressure oscillations. It would vary from 13-20 PSI and it would run unevenly at 12K. I had the 124J integral silicone firesleeve hoses, the extra fire sleeve I believe insulated the fuel line better, and prevented the onset of vapor lock. I also replacd the fuel pump at that time but I think the problem was the hose and the heat.

romair · August 29, 2015

Byron - what kind of additional fire sleeve did you use to insulate the 124J hose? I have the same hose and also I am seeing oscillations.

**N201MKTurbo** · August 29, 2015

I would suspect the fuel selector.

**jetdriven** · August 29, 2015

I used the fire sleeve from the old fuel hose. It was tight but it fit over the 127J hose. I suspect in this particular instance, it heats the fuel enough to cause the mechanical pump problems to lift the fuel

MooneyBob · August 29, 2015

.

Joe Larussa · September 1, 2015

Ok so I bleed the fuel pressure line from firewall to gauge. Better yes- perfect no. Not giving up.

FloridaMan · September 1, 2015

This is a shot in the dark, but could a partially obstructed tank vent cause this?

Joe Larussa · September 2, 2015

That's what I was thinking. Did the best I could do at blowing through the vent with my lungs. Seems

pretty open.

FloridaMan · September 2, 2015

This accident involving an experience pilot related to fuel tank vents bothers me a bit: http://www.ntsb.gov/about/employment/_layouts/ntsb.aviation/brief2.aspx?ev_id=20001205X00519&ntsbno=MIA99FA140&akey=1

I'm not sure if it relates at all, but it goes into a lot of detail as to where and how things were blocked.

Marauder · September 2, 2015

This accident involving an experience pilot related to fuel tank vents bothers me a bit: http://www.ntsb.gov/about/employment/_layouts/ntsb.aviation/brief2.aspx?ev_id=20001205X00519&ntsbno=MIA99FA140&akey=1

I'm not sure if it relates at all, but it goes into a lot of detail as to where and how things were blocked.

Experienced pilot? According to the FAA accident report, he didn't even have a multi rating. This is the Pressley accident. Reading over the list of things they did; wrong propeller installed, obvious oil leaks, Walmart battery installed, I'm not surprised this accident happened.

If they didn't care enough to put the correct propeller on or to drop 3 quarts of oil into each engine without determining why they needed 6 quarts, do you think they even bother to check vent lines?

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N601RX · September 2, 2015

I didn't reread the report,once before was enough. If I remember correctly there were a few spark plugs missing also.

Marauder · September 2, 2015

I didn't reread the report,one before was enough. If I remember correctly there were a few spark plugs missing also.

Yeah, one plug was loose in the hole and another missing.

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**jetdriven** · September 3, 2015

He killed his own son to make a quick buck. Yet every year or so someone asks why they shouldn't buy one of his rebuilt wrecks.

Joe Larussa · September 8, 2015

Problem solved. Plugged restrictor on the back of the fuel pressure gauge !

Joe Larussa · September 28, 2015

Okay I lied! Problem still here. Help!

PTK · September 28, 2015

He killed his own son to make a quick buck...

Technically not exactly.

His son made the conscious decision to fly an unairworthy airplane. He didn't have to do that. He could have refused. He should have refused exercising his final authority as PIC.

If you read the NTSB report carefully where it talks about the logbook entry that the father stated he had made and supposedly was with the wreckage but never found, he was asked to but never produced a duplicate. The father here does in essence dump the responsibility for airworthiness and blame on his son!

Very sad but true!

"...On June 7, 1999, a statement dated June 5, 1999, reportedly signed by the accident pilot's father, Jerry Pressley, A & P certificate number 237587185, was sent via facsimile to the NTSB office located in Miami, Florida. The statement indicated "During our last conversation on the telephone you stated that you needed a written statement from me concerning the ferry permit for N6600. I did not sign any document for the aircraft stating that I had inspected the aircraft and found it airworthy for the ferry flight, nor did I sign any statement that could be interpreted to mean anything similar." No contact was made by the NTSB investigator with the attorney between May 10, 1999, and June 7, 1999. Numerous attempts to obtain a written statement from Jerry Pressley regarding his installation of the left propeller through his attorney, were unsuccessful..."

Edited September 28, 2015 by PTK

**jetdriven** · September 28, 2015

Like I said. He killed his own son. I'm sure he will be more careful with some random buyer.

Marauder · September 28, 2015

Like I said. He killed his own son. I'm sure he will be more careful with some random buyer.

I'm not sure his son was an A&P, so it was up to him sign it off. Am I missing something?

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PTK · September 28, 2015

Like I said. He killed his own son. I'm sure he will be more careful with some random buyer.

Certainly not letting the father off the hook but does the PIC bear any responsibility?

Did he do his due diligence before deciding to fly that airplane?

He knew the circumstances surrounding it and its airworthiness status. Why did he choose to ignore it?

Edited September 28, 2015 by PTK

**jetdriven** · September 28, 2015

I'm sure an upstanding, moral man such as Jerry Pressley didn't goad, coerce, persuade, plead, conceal information, or otherwise pressure him to fly.

Edited September 28, 2015 by jetdriven

PTK · September 29, 2015

I'm sure an upstanding, moral man such as Jerry Pressley didn't goad, coerce, persuade, plead, conceal information, or otherwise pressure him to fly.

I don't know if he did or not.

But if he did and was successful in persuading the PIC to act against his better judgement, then the PIC bears more of the burden!

Edited September 29, 2015 by PTK

Marauder · September 29, 2015

I don't know if he did or not.
But if he did and was successful in persuading the PIC to act against his better judgement, then the PIC bears more of the burden!

Really? Are you a father?

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PTK · September 29, 2015

I don't see the relevance Chris.

Please explain. I'm really trying to see your poit of view.

Did you read the NTSB teport in its entirety?

Edited September 29, 2015 by PTK

Marauder · September 29, 2015

I don't see the relevance Chris.
Please explain. I'm really trying to see your poit of view.

Did you read the NTSB teport in its entirety?

If you need me to explain this, I'm not sure me explaining will help. Based on the findings of the accident report, and yes I have read it, a number of times, if you were there, had an A&P license in your wallet, would you have let anyone fly this plane?

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