ATR Power Levers
 

Anybody know why ATR power levers are different sizes?
Being asking a few guys who have been flying the machine for a few years and no clear answer as yet. Any ideas out there?

brgds,

GP

maybe same as for many props?

critical engine

yes and so what ?? most of the twin engine propeller aircraft (piston and turboprop) have Eng 1 as a critical engine !!! do other A/C have a bigger PL1 than PL2 ? I dont think so ! :confused: :ugh:

Do you mean that the left is larger than the right, or different from aircraft to aircraft?

Ah, sorry just missed the last post.

http://www.bytephoto.com/photopost/d...ower_Lever.jpgI've noticed the same with the Aero Commander (turboprop), but I think the reason for this is because the left power lever houses a GA switch and horn silencer, maybe this could be the reason?

http://www.!!!!!!!!!!!!!!/open.file/0943680/L/

on the Dash8 both are the same size :) ...

Same as on the SAAB 340, same size!

Aussie

Is it maybe because, after landing and engaging number 2 prop brake, you would taxi on number 1?:confused:

Wheres all the check and training ATR captains when ya need em!

:cool:

Aussie

Pprune calling Hugmonster..........

Reason is severly banal... insufficient clearence between PL2 and CL1, which was easier to correct by cutting off half an inch of PL2 handgrip than by repositioning PLs and redesigning the entire throttle quadrant. In other words, originally there was no room for F/O's LH thumb. Difference is visible here:

http://www.!!!!!!!!!!!!!!/open.file/0706707/L/

BTW, ATR has plenty of rudder and there's no noticable difference in controllability during EFATO no matter which donkey quits (in a sim, anyway). Also all systems can be powered from either engine, therefore there is actually no critical engine on ATR. Also single engine taxiing is done on eng no2 and I have certainly never engaged prop brake during taxiing, nor I can think of any reason why should anyone want to do it. Both PLs have the go-around button, no1 for capt's thumb, no2 for F/Os.

Is it an SOP to taxi on 1 engine????

Do airlines actually do this?

Aussie

QUOTE=Clandestino;2903149]Reason is severly banal... insufficient clearence between PL2 and CL1, which was easier to correct by cutting off half an inch of PL2 handgrip than by repositioning PLs and redesigning the entire throttle quadrant. In other words, originally there was no room for F/O's LH thumb.

Thanks for that Clandestino... seems like the best suggestion so far. I was kinda thinking that is was possibly some kit left over from a previous design etc.

So why is PL1 not as small as PL2 then ? :confused: :hmm:




Yes, generally, ATR pilots feather engine 1 after landing for taxiing to the stand ! One important thing is to check the hydraulics and obviously the brakes !

Our SOP's - in my ATR days - were to taxi with BOTH engines running, and props full fine..... Just to avoid the total loss of hydralics:ok:

Does this mean having the condition levers fully forward? Isn't this rather noisy? I didn't think it was possible to choose the blade angle, I thought this was a function of the overspeed and underspeed govenors? (or dependant on PL position during beta mode)

(not a turboprop driver so just asking) :ok:

condition levers control fuel - not prop governor.

power levers control fuel - prop lever control the governor, which sets an rpm, which dictates blade angle.

I thought the ATR only had PL's and Condition L's. Where are the prop levers then?

Now I'm confused! :bored:

I thought that the Power levers control fuel flow, while the position of the condition lever determines the RPM and hence the U/S and O/S govenors will adjust blade angle to maintain that RPM. When the PL are retarded to beta mode, the PL controls blade angle and fuel flow is used to control RPM????

There are several notches on the condition levers :

Fuel Shut Off
Feather
RPM -> Auto and OVRD (for PEC A/C) or Mini to Max (for classical versions)

;)

But that depends on which ATR model you fly. The posh ones with PEC's and EEC's use a little rotary knob to select the power rating which in turn selects the RPM. No condition or prop levers here (in the traditional sense!).

PM

Regarding the single engine taxi: it's ATR's original SOP to start eng no1 during taxiing out and shut it down during taxiing in, but we don't do that anymore. Miniscule fuel and time savings are not worth the extra workload and if BTC and GCUs work less than optimally, one may lose normal braking after shutting down an engine.

What ATR calls condition levers (CL) are actually prop levers with aditional fuel shut-off function, rendering classic CLs unnecessary and reducing number of levers mounted on throtle quadrant. On old ATRs (42-300 and 72-200) equipped with electronic control unit/propeller control unit (ECU/PCU) CLs set prop RPM between 77 and 100% (100% is 1200 rpm) but only in flight. On ground ECU acts on HMU so to maintain minimum of 70.8% rpm when blades are fully flat. When you push PLs forward, PCU maintains 70.8% rpm (unless you push them very far forward, that is) but blade pitch starts to coarsen, giving forward thrust. You can move CLs anywhere between max and min rpm when on ground and it will make no difference. Trouble can develop when you set PL to take off position with CLs not set to max rpm - overtorque is guaranteed (luckilly I did it only once and it was in sim) and that's why CLs are always on max rpm for taxiing.

Surely the reason no.1 PL is bigger than no.2 PL, is so the Captain can say to the FO "mine's bigger than yours"





I'll get me coat

Finally Explained
 

Got an explanation from an engineer and seems to make sense. He reckons it is to do with the syncophaser and acts to highlight which is the master engine and which is the slaved one. The master being the number 1 engine on the ATR and hence the number 1 power lever handle being wider.
Now surely some training captain will be impressed with that piece of trivia late one night in the local over a few beers :ok: