I learned about flyng from that

[rcastillo]

Hi:

Today I was flying back from MRMR, a private turf runway in the north pacific coast of Guanacaste, to our home base ar MRPV; the whole preflight was perfect, no issues at all, the engine check and all.

I have the habit, good or bad habit but I have it, of leaning out as part of my magneto check, so I am sure the mixture control was working fine up until there, and again, all preflight and pre take off checklists perfectly ok; we started the take off using the soft fied technique, this time with 15° flaps to try what some thread was commenting here a few days ago, that setting worked perfectly, we were off the ground quickly and started ascending at about 1000 ft per minute.

This was just the second flight after we installed a JPI 450 so I am still getting familiar with it, after passing the after take off checklist, I pulled the mixture a little to 1300° F which was showing about 19 gal per hour on the JPI-450, (at 3000 ft indicated, we are normally passing 5,500 ft densitute altitude) I continued climbing and about 5,000 ft I noticed the EGT close to 1,500; of course, that called my attention, I was sure I had not pulled the mixture that much, the original fuel flow indicator was indicating just a little over 10 gal per hour and the JPI 450 was indicating a little over 12, so I enrichened the mixture but all I got was the JPI 450 to show 13.6 gal per hour and the EGT just to settle around 1480, our engine peaks about 1525. I checked the fuel pressure and it was well inside the green arc with about some 22 inches, cylinder temp was just over 400° F which was a little on the high side but no to get scared about it, oil temp and pressure were also OK; so I decided to continue and monitor the situation.

We continued climbing but I decided to settle at 7,500 since it was already a good enough altitude and the temps were just ok so I was trying to keep them under control by gaining some airspeed to help the cooling and to not to make the engine suffer with the high EGT during climb and risk raising the cylinder head temp even further; I decided not to touch too much the engine controls since the low fuel flow, which was now just about 12 GPH, and EGT were obvious indications of something not being perfect; appart from that, everything else was just perfect; now it was time to descend and I didn´t want to cut back too much on power since I was affraid that I would be inviting the unwanted silence of a dead engine, so I kept the Manifold pressure to 20 inches during the whole descent, which where I keep it anyway, but on final approach I kept it just at 18 inches until we were above the numbers and kept a little power until touch down, when I retarded to minimum, the prop just stopped; by then, we were still rolling, so I made the first exit without power, I tried to restart the engine, but it just didn´t; so we had to push it to the hangar, which thank goodness was very close to the intersection we stopped.

I don´t think this event has to do with the installation of the JPI 450 but rather with a mixture control adjustment that was done while we were testing the new 450, we felt the mixture was too rich and then the mechanic adjusted it. I guess something got loose from that adjustment. On the outbound leg we flew on Friday, everything worked fine.

I had with me my wife, our 17 year old son and our 7 year old daughter, all them took this very calmedly and were confident we made the right decisions; my son was flying copilot and we were commenting the abnormalities during the flight, so they were all aware of what was going on. Ah...we modified the route a little bit just be closer to potential landing sites.

Do you guys agree with my mixture control theory or do you suspect something else?


Thanks and best regards,

 

[dgeib]

Re: I learned about flyng from that

Just glad you and your family are safe and sound.

Hope you are able to find the cause quickly. Obviously fuel related, so mixture adjustment might be the first place to look since that was the last adjustment. I assume mixture was full rich for landing which adds other fuel starvation possibilities.

 

[rcastillo]

Re: I learned about flyng from that

Thanks Doug, the fuel mixture was full forward since I first noticed the high EGT, I pushed it all the way forward and didn´t pull it back at all.

I am meeting with our A/P tomorrow to troubleshoot this. But I want to be there when they check it since I want to see this myself.

 

[wab003]

Re: I learned about flyng from that

Are you injected Roberto? If so, was the JPI installed before or after the fuel servo? It is generally installed after (spider side of the servo) because it is easier for the mechanic to get to that location; however, it will cause erratic fuel metering and could cause the situation you describe. MUST be installed on the supply side of the servo.

Did you adjust the idle mix star wheel? Too lean can starve the engine at idle but shouldn't adversely impact the flow at full throttle. If the retaining spring broke or is now gone, that can cause big problems at low power (close to idle) but will normally run OK at full throttle. Also possible that the JPI install could have either broken loose some debris in the fuel lines or the hoses weren't cleaned thoroughly after fabrication and that could cause the servo inlet screen to be choked off with some junk.

Possible that the install created an interference w/ the mix control arm but that should have been checked before return to service signoff. Guess you never know for certain...

 

[Steve]

Re: I learned about flyng from that

Not sure if this has any bearing on troubleshooting or not but was the fuel pump turned on and or off to determine if there was any difference in the indications?

 

[rcastillo]

Re: I learned about flyng from that

The fuel pressure was ok, it was well inside the green arc, so I didn´t want to try the electric pump, I'll go to the airport in a couple of hours to check to meet with our A/P.

 

[Pete]

Re: I learned about flyng from that

Bill, the STC for my FS 450 called for the flow meter to be installed vertically between the servo and the spider.

 

[davloose]

Re: I learned about flyng from that

Bill, the STC for my FS 450 called for the flow meter to be installed vertically between the servo and the spider.

I know my plane/engine installation instructions are as Bill described, before the servo, but as pointed out, many install it after. Other engines, fairly similar, have instructions to install betwen servo and spider. With the discussion that was had before, I called JPI and spoke to a technician, and asked if there was any problem from my mis-install. They told me there was no problem installing that way. FWIW..

 

[rcastillo]

Re: I learned about flyng from that

hi, we found the problem...well...the A/P found the problem, his assistant had disconnected one fuel line that goes from the servo to the spider; this is not where the flow meter is installed; the assistant reconnected it but didn´t tightened it enough, so it became loose during the return flight and this was causing the odd reading and actual poor fluel flow; they retightened it, we test it, closed the clowling and went flying to test it in flight and everything was perfect again.

Thanks to all

 

[wab003]

Re: I learned about flyng from that

I know my plane/engine installation instructions are as Bill described, before the servo, but as pointed out, many install it after. Other engines, fairly similar, have instructions to install betwen servo and spider. With the discussion that was had before, I called JPI and spoke to a technician, and asked if there was any problem from my mis-install. They told me there was no problem installing that way. FWIW..

Have empirical evidence to the contrary for the 360 engine. Perhaps enough total flow w/ the six-banger to overcome the turbine pulsation. To each his own but I've been there w/ my 360 and had to revise the shop's initial install to stabilize the fuel flow. Has been flawless ever since.

 

[davloose]

Re: I learned about flyng from that

Just passing on what I heard...

What problems were you noticing? Just fuel totals that were off and not adjustable with K factor? Or actual fuel flow issues to the engine?

 

[wab003]

Re: I learned about flyng from that

fuel flow to the engine. Surmised that low flow rates allowed turbine to stall, which of course made flow measurements useless but more importantly, it was causing cruise EGT's to fluctuate. Despite what may have tech stated, it is quite clear in the FAA approved install STC docs that the turbine/transducer is to be installed upstream of the servo on the 360 engine. Unfortunately, I didn't oversee the install and the shop I used took the easy route w/o a detailed read of the inx. Live and learn. Fortunately identified quickly and resolved. (on their dime of course) Fuel used has been w/in a tenth or two total usage ever since. (following the designated K-factor tweaking)