DEEC ops

[Brett Hull]

This is for y'all operating DEEC equipped airplanes.

We're operating a Lear 35 with DEEC's. Our takeoff procedure, which I think is questionable, is to push the power up 'till you can't push it no more. Let the DEEC's stop the spool up when it see's fit.

I previously flew a 31a with DEEC's, and we figured and set the N1 on takeoff. It was very rare, usually a very hot day, when we exceeded max continuous thrust (832) on takeoff. In the 35, It's been going right up to 860 (max t/o) for every takeoff. We've also put ours in the shop for P&I, and the 35 we've leased (it has DEEC's too) had a TOLD card left in it, and they were figuring and setting N1's also.

I've never read any material that said to give'r he!! and let the DEEC's sort it out. Am I wrong with the concern here, or should I smack the boss upside the head?

 

[AV8OR]

Brett,

By NO means an expert, in fact, a newbie to the DEEC, but, I'm in training right now on the same engine on the Falcon 10. Procedure is to place pwr levers to the stops and let the DEECS handle it. It will go to 860 with a 5 min limit, and I believe the T/O performance calculations are based on a static T/O at Max Thrust. Anyway, for the Lear, I have no idea, but just two cents of possibly irrelevant info.

 

[banned username 2]

I fly the Falcon 900EX (TFE731-60) and Falcon 50EX (TFE731-40) and both are DEEC equipped...

We push the levers to the stops and let the DEEC's do the work... however we never get close to our Take-Off Temp Limits.

This is the recommended proceedure on these engines, I think Honeywell recommends checking the Take-Off N1's to calculated N1's every 25 flights to check for engine performance degradation.

 

[slickmagneto]

To much stress!!!

And on the 6th day after creating the Heaven and the Earth, God said" Let there be FADEC", and it was.

 

[Gulfstream 200]

I also flew a Lear 35 with DEECs (maybe SN 418 or something...)
we just pushed em up all the way, but heck, we knew no better.....

 

[mike]

Hawker's work the same way. Power levers to stops and monitor n1 and ITT. The card maybe there to check target N1. We figure it for each takeoff.

 

[passion4flying]

I fly for wal-mart. we have quite a few lears. Every take-off we figure out the N1 power setting and set that for take-off. I think that maintenance is to adjust the setting on the DEEC's that when you reach the stops on the power you are supposed to be producing max power for the conditions that exist. I would not take the power to the stops. There are time and temperature limits that will be exceeded if you just let her rip. FSI told me to try not to exceed the N1 take-off power. That setting is producing 3500 lbs of thrust. If you are using a higher number you are producing more thrust that the engine is not rated for. Yes, the engine will handle it but over time, it may break down quicker. Just my thoughts.

Passion

 

[GREAT LAKES]

DEECS

Figure the N1 for each takeoff. Its in the book for a reason!!!

 

[beytzim]

On the DEEC on the 731-5, we push the throttles to the stops. The pre-computed N1 is a minimum N1. Not a max N1. This is the min N1 at 80 kias per the AFM. At 80 kias, we must be within 1% (i.e. no less the 1%). Otherwise, the DEEC or engine is not producing the power necessary for takeoff.

So, you MUST confirm the N1 at 80 kias. Personally, I've seen it right on to as much as 2% off. The AFM does explain that the ATIS and the ambient temp on takeoff can be significanly different....so supposedly its ok.

For temperature sake, i've seen it is as high as 960 (978 being max) and as low as 900.

The stupidest thing on the DEECS on the -5 is the green light for climb. It's supposed to maintain no more than 100%...supposed to. I've seen go up to 100.3%

I recall that on the -3, the recommeded climb power setting was pretty interesting: set max cont N1 at 15,000'. Note temp (usually around 845) and use that same temp all the way up.

On the -2 EEC, I usually climbed at 800 degrees. 832 if you really needed it.

 

[ultrarunner]

DEEC Operation

N1 DEEC's primary function is to set a minimum N1 for the day. Maint. does NOT get in there and 'tweek it'. This is a function of the DEEC's and the input's they recieve.

N1 for the day should always be computed and "carded". That's why its there, and that is what the PNF checks. If you don't, how in the world would you know the DEEC is giving you the correct N1?

There are a bizzion issues that effect temp during TO, and it would be odd if you're reaching the temp limit prior to getting N1 for the day.

In any event, it most DEEC applications, the throttles get set to the stops. This is how a Falcon 10 is operated. I have not flown other DEEC equiped airplanes, but here is a thought for you....

Take look at the DEEC Supplement that's in your Airplane Flight Manual. You did review it, right????