Power Checks

[100ft]

I''m back again Mini. I was in the bathtub.
Downwash accurately paraphrased my earlier input regarding the informal frequent power checks. Pls keep in mind that my experience is limited and is also limited to piston poppers. That''s why I am glad to read some responses from a couple of experienced guys incl engineers (407 / frenchwrench).

 

[Rotorhead]

The Bell 206 required power checks that we did every fifty hours of airtime or once a month (If I remember correctly). Being fairly busy a few years ago, I usually did one for each logbook page.

On a multi engine turbine machine, we do daily trend checks which are just that, a trend check, so if anything is changing, such as MBG pressure or temperature, it can be picked up between scheduled power assurance checks (topping). Also, there is a check that we do on the SK61 that is called a Total Performance Check done every 300 hours or after maintenance requires it.

RH

This week, I am in a camp at the mouth of the Orinoco River in Venezuela and cannot get out on Hotmail or Yahoo with the restrictions on the oil company`s Internet connection. So if anyone is wondering why I haven`t been in email contact, this is why.

 

[DGP]

Frenchwrench said it all,if the gauges in the dash have'nt been checked recently they are the first things to be suspected if you are getting some bad numbers.Also said and I agree is Know were you start from if you are switching to a lot of different aircraft.Under similar conditions and weights pulling a set torgue should get you the same TOT.If not ask the wrench if the gauges have been checked lately.PS...if the values are small I wouldn't bugging the wrench unless you want a C wrench in the ear!!!....I'm a wrench as well as a pilot.

 

[Toni]

It would be great for the low timers in this forum if one the more experienced pilots can explain how he makes the power check of a 206 from the first step til the last step!!!!!
And maybee some good advicements!!
Thank''s in advanced

Toni

 

[407 Driver]

206A/B/B3 Power check...Vertical climb method.

-Altimeter to 29.92
-All air systems off (bleed, anti ice)
-Generator off
-Cruise at target altitude for a few minutes and record OAT.
-Descend 500'' below target altitude, reduce airspeed to 0
-0 speed climb through target altitude at Max Q or Max TOT
-Record Nr, N1, Q, TOT when climbing through target altitude.
-Graph results, using correct power check chart for engine (C20, C20B, etc)and installed equipment (particle separators, etc).

 

[downwash]

Nice, tight summary, 407. How come the guys that write the books can''t do it like that? Probably because they get paid by the word?

 

[MINI]

Okay,time to be a little more specific.What,if any of the companys you guys and girls work for require you to do power checks,and how often do they require you to perform them.ie after maintenace,every 25 hrs or what?

 

[downwash]

In our house (a single engine shop), at least every 100 hours, in accordance with the flight manual and, if available, accompanied by maintenance pers.

 

[MagSeal]

is there a requirement in the CARs about power checks? (Anyone with intimate knowledge on those dastardly publications???)

I seem to remember Canadian having any number of different ways, from every 50 or 25 hrs, every 7 days, to every page in the log. At the very least we were required at the scheduled 100 hour inspections.

 

[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.