Power Checks

[downwash]

We do like to have one on every page, too, Mag, but the minimum is every 100 hrs.

 

Don''t think there''s anything in CARs (why would they commit to a standard they don''t have to, especially if the manufacturer doesn''t?).

 

When you get as many opinions as a CHL can, you''ll get some pretty complicated standards.

[frenchwrench]

nothing in cars that i see, but only here that an engine degrades 1/10 of a percent roughly on 100 hrs on a 2x6. I see plus 30 degrees one week become plus 5 on the 500''s after a driver change. a little bleed air away from an allison and she shows it,as the antiice and heat valves are crap. I have seen so called weak engines being sent to standard to get test celled and come back good with a check your guages please note...

[cap]

I agree totally with 407/Downwash on all. I do however, believe a trend check will keep you out of trouble much quicker than the power check. Blackmac and I will definitely disagree on this one, I guess. IF, that trend check is done on a medium as it should be and registered in an appropriate, on-board, in-the-pocket manual, then that record is there for a pilot to check a year later. My authorities on this: Yves LeRoy, Howie Gatin, Bob Cameron/Tony Kennedy.......,the last two late of Standard Aero. I've seen the cost of an O/H for a -13 halved because the engine APPEARED to be functioning properly but the EGT records in that manual showed otherwise.

 

Also, if that Q guage is reading 3-5% while static and is a wet line guage, you are wasting your time doing a power check. There is no such animal as residual pressure in that wet line, so you have no idea what it's reading at the top end. Maybe you got 100% and maybe you got 97%........who knows? Other than first hand experience with same, my sources for this info are also the above named gentlemen.

 

 

[LDP]

We do daily trend checks and a power check every 25 hours. I agree that the trending is the best (earliest) way to detect a problems.

[CTD]

Trending is the way to go, preferably daily, and logged / graphed in a separate book.

 

Power checks on the 206 series are useless. If the ship fails at 2000'', climb to 8000 and she''ll pass. RR and Bell simply will not address the issue, and it would never be certified today like that. A spec + 15 engine at sea level should be a spec + 15 engine at 10,000''.

 

Careful with that zero-airspeed climb at altitude. That thing will swap ends faster than you can say LTE. 

[frenchwrench]

even Allison says they look at 20 degree differences as errors in recording etc.An open antiice costs 38 hp at the higher ToT''s. If the rod rattles, she is getting hot air. those bleed air heat shut off valves are rarely tight either. that is the first thing they want you to do, plug them off.the N1 needs to be up past 95% also.next time you use the vibrex 2000 get the engineer to read the rpm on the N2 you''ll see 100 isn''t 394.

[GoldMember]

CTD,

 

I know that this may turn into an episode of "Old Dog Teaching Relatively Young Dog A Few Tricks", but is a 206 power check really useless? You can''t always have the same temp, but checks done at consistently the same altitude will show a change in engine performance. If they''re useless, why do them at all?

[CTD]

Who are you calling old?

 

A series of power checks, done at the same altitude and similar settings are called.....trend checks. They will show you the changes you speak of, and signal impending trouble. They are not intended to show engine health against a min spec.

 

Power checks tell you one thing and one thing only - the relationship between your installed engine and the minimum spec power, and therefore can achieve the performance specified in the RFM. If an aircraft fails at one altitude and passes at another, this is truly useless. I have fought that battle with Bell and RR, and nobody will pony up the dough to make it right.

[DGP]

Once again Frenchwrench is right on.WE had a jetbox out west that everyone said was a dog.Couldn''t lift a weiner off a plate(black bart''s second favourite saying next to you old potlicker)Turns out after checking the N1,TOT,NQ,we hooked up a 8500 and found the N2 was running at 96%.Another common problem on old 206''s is the oil line for the NQ is starting to swell shut,giving false readings on the gauges...have a good one...PS...CTD when is the golf tourny thing happening this fall...would like to attend with DDF.

[CTD]

Yes, Frenchwrench is right. Any power or trend check can be seriously affected by instrument inaccuracy, and as little as 1% Np delta will toss the numbers out the window. I''ve also seen the OAT out to lunch, and that''s a biggie as well.

 

DGP - Longranger and family are in the process of moving to YQM this week, I expect to hear from him soon. The TRIC will definitely be on the agenda. He''d hoped to have one earlier in the season, but it''s looking like the move has nixed that. I''m thinking we''ll be on for the week after the spray is over. We''d love to have ya, and it''s a great weekend.