high press compressor

[ch72bob]

C-130 world, a month ago, I got a high press compressor! you all know the test you have to do @ 900°C TIT, oat-Paltitude and reading from a straight line on the indicator. We tripple checked all of our values before we startet to troubleshoot.

We changed : T-block, harness, thermocouples, Y-cable

We checked out TD amplifier.

Still the observed we had 120Psi and calculated 117Psi.

The is the first time in my career i\'ve seen this.

I\'ve to check the remaining potentials of the compressor and turbine.

someone a guess?

OAT:44.79°F

Pa:29.74 inhg

dRB

:evil:

[pjvr99]

I bet your performance was also around 113%. Not a problem - I had one about 2 years ago. Spent more than a week looking for the problem, until I noticed that the CDP matched the \'Air Start\' pressure guage. I confirmed by adding a third direct reading guage. You have one of the 1-in-1000 engines where the turbine, compressor and associated components match perfectly, coupled to the atmospheric conditions. Just make sure it\'s installed on an INBOARD position, and make a clear entry in the a/c forms. There\'s nothing wrong with it!!

[Lkuest]

Wow, 120psi is a lot. On a brand new engine, I wouldn\'t read too much into it. I did talk to a guy though, who said he\'s seen multiple engines on the same aircraft with at least 116% efficiency. He was convinced there was something wrong with them, but the engine troop that came with the plane insisted everything was legitimate. They ended up changing the engines out because of excessive compressor stalls. How they got up to 116%, I have no idea, but it may have involved some unapproved modifications (guard bird).

pjvr99\'s answer sounds good. As long as you don\'t suffer from compressor stalls, you should be good to go. One question though. Is is a -7 or a -15? If you have a -15, everything is golden, until flightline has to do overtorque inspections once a week. If it is a -7 engine, the aircraft the engine is being installed on doesn\'t have bleed air regulator valves. A high efficiency engine can be a problem on E-models, and we\'ve changed an engine or two for being too powerful, and for some legitimate reasons. The problem is that if an engine\'s output air is not regulated, and it is a lot stronger than the other three, it becomes the only motor supplying air to the other systems. The flight crews check performance with the bleeds open and the A/C and ATM running. The strongest motor becomes the only engine losing air, and therefore power, and your 113% engine can turn into a 94% engine real quick, often hiding a legitimate low power engine that isn\'t putting out any air to the manifold. Maintainers check performance with the bleeds closed, so the problem likely wouldn\'t be found until the engineer checks power before takeoff.

There is no maximum efficiency limit in the tech data, as long is there are no other problems associated with the engine being high power. You may have just found the four leaf clover. Congratulations.