Power-check How-to

[Over-Talk]

Ray, I agree that the A-star charts don't give you the same + or - figures that a 206 chart will, but you can tell how good the Arial is working by seeing how close the result is to the diagonal correct/incorrect line.

With a deteriorating engine you will see the results moving from the correct to the incorrect area with each power check.

[smoothair]

Ray, I agree that the A-star charts don't give you the same + or - figures that a 206 chart will, but you can tell how good the Arial is working by seeing how close the result is to the diagonal correct/incorrect line.

With a deteriorating engine you will see the results moving from the correct to the incorrect area with each power check.

 

 

yes, arriel only states that you indicate correct or incorrect. I have used the HHS program for a number of years now. It indicates a number + or -. If you are with an aircraft for any length of time you have a great record for trending. In the past if i was with the same machine. i would measure in mm the distance off the line. that would give a good trend as well as over-talk stated.

[InspectorGadget]

Bringing back this for a B model question. Trying to find a "Sand Filter" power check chart in the RFM. Supplement 9 is the sand filter supp but no charts there. I had heard you use a BA sand filter chart but this doesn't make sense to me.

 

Anyone help me out on this?

[ray]

Don't have a 350B in the fleet so I couldn't look it up.

 

What does the flight manual supplement for the sand filter say about performance/power checks?

[happyfeet]

Download the trial version, and evaluate. You really have to blow up the graph in the manual to get an accurate reading, or then again it may be my eyes.

 

www.hhssoftware.com/powercheck/

 

Makes life easier.

 

Good luck

 

HF

 

 

[InspectorGadget]

Ray, no such thing.

Just heard back from P.S. at Eurocopter and apparently the sand filter supplement was never published for the B model. Go figure. Got the chart from it faxed over now and the engines look better on paper now. Talk about confusing... These FDC kits mix everything up. I am still not convinced either way.

 

Happyfeet, I have the trial already. Doesn't show sweet eff all for inlet choices for B models.

 

Eurocopter, if your listening, your power check procedures are great.

 

For fire starter. Lol.

 

Thanks Ray and HF.

[skullcap]

Inspector Gadget

 

At one company I worked for years ago they converted B's to BA's and we found it very strange that an engine that was passing power checks fine in B was now marginal in BA,,,,and was explained to me that since the BA draws more horsepower out of the same engine(88% compared to 83%) then the engine has to be more efficient and the sandfilter is more restrictive thus new charts for this model.

 

As for the FDC filter we have noticed a strange thing in B2's, when the OAT is cooler the performance checks are much better whereas the margin in which an engine passes or fails has in the past without the FDC been the same(an engine power check chart should be consistant in allowing you to determine the power available no matter the temp or altitude)

 

The JR3 used to have the opposite issue until above 4000' due to efficiency of turbine(not bleed valve as many thought) but I think the charts are better now.

 

 

[Three_Per]

yes, arriel only states that you indicate correct or incorrect.

 

when the chart is used correctly you can plot back to the bottom and ascertain how many %tq the engine is passing by (or failing by) just like the B3 shows you on the VEMD. I cant really explain how on the forum I would need everyone to gather round and show you in person on the chart

[InspectorGadget]

Three Per,

I thought power checks were to show by how many NG an engine passes by? You say TQ? I could be wrong though. The HHS program gives you it in a + or - NG.

 

Skullcap,

Thanks for the info. Pretty interesting stuff. A lot of smoke and mirrors it seems. We are still working on finding just the right charts and trying to solve this failing engine (who by the way is a stump puller if you ignore the chart). Swapped Mo5, hasn't seemed to help yet. We are working our way through the Turbomeca troubleshooting chart. Next stop, a boroscope adventure in the Mo3!

 

Thanks all!

[skullcap]

 

 

If the aircraft is performing fine then you need to have a good look at torque indicating system, ensure the proper reading for mo5 is being used and that the conversion for bar to psi if using psi reading gauge.

 

Also, check the rotor rpm is accurate(can throw off power checks) and if necessary check rigging of anticipator and low pitch settings are correct.

 

Have never seen an airleak cause failing engine in Arriel.

 

If you do have sand filter ensure all swirl vanes are clean, we do it every 100 hours in lama and helps.

 

Bleed valve condition is very important though, ensure the thing isn't all rattly.

 

Ensure oil pressure is fine, have change one oil pump to fix power check as well.

 

If aircraft is not performing well then follow the procedures but something that have found solved marginal engines in past is to do the check where you run the engine and see if fuel is leaking back to tank, if there is and the valve is changed to stop this do another power check. Have seen this fix two engine power checks. It was explained to me that this is metered fuel thus causing lower power but a bit smoke and mirrors too.