EMB 120 Prop

[The_Russian]

Just curious,

How many of you operate the props at 80% during cruise flight? If you don't, why don't you?

 

[MYFpilot]

Just curious,

How many of you operate the props at 80% during cruise flight? If you don't, why don't you?

Not so much in straight and level cruise but I do it all the time fo the longer descents. According to SkyWest EMB SOP APPENDIX B Page: B-42
PERFORMANCE Revision: 08 STANDARD PRACTICE 3500 Date: 01 JAN 06
36. EMB 120 Cruise Torque Chart & Settings – Procedures
...D. SkyWest Airlines cruise is conducted at NP of 85%.

So that's probably why.

 

[deluxxx]

85% according to standard opps. WHy do you use 80? By the way have you actually flown any Soviet planes?

 

[7dustfan]

80% doesn't give the same cruise TAS as 85% NP.. 80% is good for cruise descents... gives less drag during descent but jack schit for pull during level cruise.

 

[The_Russian]

I see the reason to maintain 85%. Better TAS and icing protection. The reason I use 80% (on occasion) is because it is quieter, saves fuel, and reduces the strain on components. And, it definitely reduces the drag in the descent. Truthfully, I am not in any rush. I like to block high, baby!

The reason I posted was an inquiry into any reason that this may cause a mechanical problem or exceed any limitations. Even though I know it doesn't exceed any limitations, my FO's keep saying that I am and I can't seem to get them to justify their statement. From reading the chart in the AFM I am well below the 1305 SHP line and have a max TQ seting or 84% at that NP.

Also, does anyone use a Schedule A climb?
90% NP out of 12,000.

I would like to hear more about his 80% thing. Keep 'em coming.

 

[flyboyike]

By the way have you actually flown any Soviet planes?

No, she hasn't, she doesn't even speak Russian, regrettably.

 

[The_Russian]

No, she hasn't, she doesn't even speak Russian, regrettably.

Shhhhhhhhhhhhh!!!!!!

 

[The_Russian]

You want me to take the soviet planes off there? I thought it was a bit fitting with the name and all. Although, I cant wait to take a shot at flying the MiG 21. Personally, I have a great love and respect for eastern built aircraft. Pure steel and black smoke!

 

[Doc Holiday]

Well how does your company tell you to do it? From your comments it sounds like they don't tell you to set the Np at 80% for cruise, or your FOs wouldn't be questioning you about it. Of course you aren't exceeding any limitations, but it probably isn't the most efficient way to run that airplane in cruise. You get paid to fly someone else's airplane, so don't make your own program. Do it the way they want it done.

Apparently 80% Np, 25-35% TQ, 1800 FPM, and 220 KIAS is the least drag configuration for descent. I find it works well for descents into airports that don't require intermediate level-offs (smaller airports).

I am a fan of the 90% Np climb above 12,000'. Especially if you need to climb up into the flight levels. It is much more comfortable for the pax and FA as the noise level and vibrations are reduced. As long as you don't let the airplane get too slow (less than about 165 KIAS), it works well and will get you up into the mid twenties. I have found that trading climb rate for airspeed once you get above FL180 will let you climb at 170 KIAS and 500 FPM up to FL250 most days.

 

[deluxxx]

90% climbs are much louder in the flight deck, and since I am up there 120 hours a month the less noise the better. You will have longer block times with 90% though.

 

[FlySacto]

90% climbs are much louder in the flight deck, and since I am up there 120 hours a month the less noise the better. You will have longer block times with 90% though.

I brought along an SPM once on a flight and we attempted to determine the straight scoop on the 90%vs100% climb. I haven't tried it in the cabin but we found that with either setting that you could move the meter around and find 15db change just moving the meter less than a foot in any area. Bottom line, WTFK! If nothing else the 90% climb is of lower frequency and doesn't sound like we are fighting our way to the top from the take off. The climb charts suck though, and you'll really be building block if you use them into the mid twenties. I watch the temps and keep the torque under 84% during the climb. The limit is 800 degrees if we need it, 720 when we can. 600fpm at FL200 isn't going to cut it.

 

[N1VIBS]

Be very, very, very careful with the E120 props!!!!

 

[ERJFO]

I herd at Gulfstream the F/O's have to pay more if they want to run it above 80%.

 

[Cardinal]

I'm just scared of the props, period, so I run at book RPMs - 85%. The thing with props is that what "feels" quiet and smooth may in fact be resonating at the natural frequency of some important part, which may fail from fatigue at an innoportune time. It's the same reason we don't go CL's Max until cleared for takeoff. Given the history of these death scimitars (where is 14RF SUX?) I do as Embraer asks and try not to think about them. If the noise bothers you, get a better headset, seriously.

 

[flyboyike]

You want me to take the soviet planes off there? I thought it was a bit fitting with the name and all.

I don't know if it's fitting, seeing as you probably wouldn't know half of them if they fell on you. For instance, what does LaGG stand for?

 

[The_Russian]

Well how does your company tell you to do it? From your comments it sounds like they don't tell you to set the Np at 80% for cruise, or your FOs wouldn't be questioning you about it. Of course you aren't exceeding any limitations, but it probably isn't the most efficient way to run that airplane in cruise. You get paid to fly someone else's airplane, so don't make your own program. Do it the way they want it done.

Apparently 80% Np, 25-35% TQ, 1800 FPM, and 220 KIAS is the least drag configuration for descent. I find it works well for descents into airports that don't require intermediate level-offs (smaller airports).

I am a fan of the 90% Np climb above 12,000'. Especially if you need to climb up into the flight levels. It is much more comfortable for the pax and FA as the noise level and vibrations are reduced. As long as you don't let the airplane get too slow (less than about 165 KIAS), it works well and will get you up into the mid twenties. I have found that trading climb rate for airspeed once you get above FL180 will let you climb at 170 KIAS and 500 FPM up to FL250 most days.

Our profiles state 85%. Good points and good post.

 

[The_Russian]

I'm just scared of the props, period, so I run at book RPMs - 85%. The thing with props is that what "feels" quiet and smooth may in fact be resonating at the natural frequency of some important part, which may fail from fatigue at an innoportune time. It's the same reason we don't go CL's Max until cleared for takeoff. Given the history of these death scimitars (where is 14RF SUX?) I do as Embraer asks and try not to think about them. If the noise bothers you, get a better headset, seriously.

Someone just told me there is an Operations Bulletin from Embraer concerning this subject. Apparently operation at 80% does damage to the quill and can increase the risk of overspeed. This is not confirmed officially and I have never been presented this information. Have any of you? If so, why has the limitation not been officially changed for the safety of crews and passengers? If I get a copy of this, will it effect the operation of this setting in the descent?

 

[Dizel8]

For instance, what does LaGG stand for?

With the internet these days, it is just to easy: http://en.wikipedia.org/wiki/Lavochkin-Gorbunov-Goudkov_LaGG-1

 

[flyboyike]

With the internet these days, it is just to easy: http://en.wikipedia.org/wiki/Lavochkin-Gorbunov-Goudkov_LaGG-1

And that's exactly the answer The Russian would have found. That's not the one I'm looking for, the pilots decoded LaGG differently.

One could probably find that answer on the net also, but...

 

[John Pennekamp]

Someone just told me there is an Operations Bulletin from Embraer concerning this subject. Apparently operation at 80% does damage to the quill and can increase the risk of overspeed.

There you go. This is a perfect example of why you should always operate an airplane as instructed, and not cowboy around with new procedures. There may be a hidden gotcha.

FWIW, Continental Express pulled their -120s back to 80% Np and they had more overspeeds than even ASA (even though ASA had the most fatalities). So maybe there is something to the ops bulletin.