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Author Topic: Flight idle  (Read 8723 times)

Steve binnette

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Flight idle
« on: January 11, 2016, 06:17:48 pm »
 
We are having trouble getting my flight idle adjusted.  Does anyone know the range for the flight idle setting.

Anybody have any opinions on where it should be set. 

donv

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Re: Flight idle
« Reply #1 on: January 12, 2016, 01:07:03 am »
If I remember correctly, the spec is that you climb to around 2,500 feet, full flaps, gear down, 100 knots, flight idle, and check the descent rate. Should be somewhere between 2000-2500 fpm. Don't be freaked out if one or both beta lights come on.

That is all from memory, and I could be completely wrong, but I've done a bunch of those flights in the past.

Personally, I prefer the flight idles to be near the bottom of the spec (i.e. close to 2500 fpm descent), but be aware that this can lead to potentially very high descent rates near the ground, and that can be very dangerous. See the accident we discussed in the General section...

Steve binnette

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Re: Flight idle
« Reply #2 on: January 12, 2016, 10:27:51 am »
Thanks Don, I have not heard that way of checking flight idle.  My flight idle is set at 18% with power pulled completely off.  It seems high too much residual thrust on landing etc.

Naples jet centers agree that 18% is too high but are having trouble getting it adjusted to an acceptable range. 

I had both FCU overhauled.

I like it when you pull power off you feel the deceleration.  That takes a low flight idle.

It's tricky to rig the engines and that is what we are working through.



ghancock

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Re: Flight idle
« Reply #3 on: January 12, 2016, 10:38:30 am »
I like that test too.  2500ft with 2500fpm descent rate if it's correct.  lol,  60 seconds to test it and you die.  Talk about a stressed out mechanic. :-)

Glenn
--glenn
You can't win an argument with an ignorant person,  they'll just drag you down to their level and beat you with experience.

donv

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Re: Flight idle
« Reply #4 on: January 12, 2016, 12:27:30 pm »
The test I describe should be in the maintenance manual. At least that's what I understand. I always did it with a mechanic along taking down data.

donv

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Re: Flight idle
« Reply #5 on: January 12, 2016, 12:31:02 pm »
That seems way too high. Although, it's dependent on RPM, airspeed, etc. That's why they have you set it in flight under constant conditions. The reason I said 2,500 feet is they'd like it to be as close to sea level as possible, but safe.

Thanks Don, I have not heard that way of checking flight idle.  My flight idle is set at 18% with power pulled completely off.  It seems high too much residual thrust on landing etc.

Naples jet centers agree that 18% is too high but are having trouble getting it adjusted to an acceptable range. 

I had both FCU overhauled.

I like it when you pull power off you feel the deceleration.  That takes a low flight idle.

It's tricky to rig the engines and that is what we are working through.

Steve binnette

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Re: Flight idle
« Reply #6 on: January 12, 2016, 04:20:41 pm »
Thanks for the help I will report back what is the ultimate fix.

donv

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Re: Flight idle
« Reply #7 on: January 12, 2016, 10:36:57 pm »
I had a chance to look at my maintenance manual-- I was close on the procedure, but maybe a bit too aggressive. Or maybe it says something about how the guys I learned from wanted their airplanes set up!

Anyway, the correct procedure is:

Condition Levels-- High
Gear-- Down
Flaps-- 40
Power Levers-- Idle
Airspeed-- 95 KIAS

Descend from 5,500 to 4,500 feet in this configuration and record the time. It should be between 36-50 seconds. Then, take the airplane to a stall buffet and make sure that no unusual rudder deflection is needed.


Steve binnette

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Re: Flight idle
« Reply #8 on: January 13, 2016, 08:26:57 pm »
That's some great info!  Thank you

I will do the procedure.

av8r

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Re: Flight idle
« Reply #9 on: April 28, 2016, 09:18:42 am »
While they currently seem to be difficult to obtain Honeywell publishes a handbook, "Pilot Tips", for 331 operators that contains a wealth of information, including their FI test procedures. If you can't locate one let me know because I have it in PDF format on the computer. I also have several hard copies that I might consider parting with.

donv

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Re: Flight idle
« Reply #10 on: April 28, 2016, 07:09:10 pm »
I'd be interested in a pdf copy. I have one for the TFE-731-- they used to make them pretty freely available.