B-737 Drivers: Question

[fluther]

N1 is usually the cause. The MD80 even has an N1 sync that does a pretty good job, even though you have autothrottles if you bring the N1's within 1% and engage the sync the engines will stay in sync.

Anyway in answer to your question, yes we usually sync up the N1's the noise gets pretty annoying towards the rear of the AC.



Furloughed a day and I miss my 80

 

[dhampton]

I sync them... Pilots with a prop background tend to notice the out of sync sound more frequently than those with a purely jet background. This probably probably because the out-of-sync sound is only about a tenth as irritating as it was in the prop airplanes. I am not aware of any "N1 sync" on the 737; however, I have noticed the N1s seem to match up and stay matched in the -700, leading me to believe the EECs are doing some kind of syncing.

 

[rudderdog]

I'd say the prop guys can hear the out-of-sync better cause they haven't YET lost the part of their hearing that the jet (military especially) guys have. Or, maybe not.

I sync them... Pilots with a prop background tend to notice the out of sync sound more frequently than those with a purely jet background. This probably probably because the out-of-sync sound is only about a tenth as irritating as it was in the prop airplanes. I am not aware of any "N1 sync" on the 737; however, I have noticed the N1s seem to match up and stay matched in the -700, leading me to believe the EECs are doing some kind of syncing.

 

[Guppiedriver]

Next time you look at the engine gages, look at the N2 gages. The N1 will be matched up perfectly and the N2 will be out of sync by about 1%. Most of what you notice out of sync in the cockpit is N2. N1 out of sync will be noticed most in the cabin.

Gup

 

[atldc9]

On the 717, the Electronic Engine Controls match EPR for takeoff, then the N1s are matched to provide engine sycnch. All electronic. We never touch a thing. Lots of gee whiz sh**.

 

[zymotic]

CRJ

Ditto what Guppydriver said. My experience in the CRJ200 is I will hear the N2's out our sync but not N1's when in the cockpit.

 

[SkyWestCRJPilot]

On the CRJ-200 sometimes I've noticed that if N1s are synced you'll get a high pitched beat with N2s out of sync. Then if you sync N2s the N1s are out of sync and you get a lower pitched beat. This seems to happen most on our airplanes that are intermixed, i.e. one engine is an "A" and the other is a "B". If that's the case I just try sync whichever has the least annoying beat.

 

[dlredline]

B-737 Sim Sync

Hey Fly Chicaga,

I spent several years training and checking in the B-737 sim. The outta-sync sound can occur with unmatched N1's. You can minimize this on the instructor's panel by reducing the "Eng. Noise Level". However, test the sound while the Auto-thrust is engaged. CAE sims. have very good N1 matching on the 73's, and absent any failures that would cause transiet and unbalanced N1 (like eng. anti-ice switch only on for one eng., or single pack operation), you shouldn't hear a sound imbalance between the engines. Contact your simulator mx personnel, there is an easy adjustment in the CPU that will help match these up. As a technique, I would only have the noise level high enough to hear thrust transitions (increase and decrease). Anything higher could create a distracting learning environment. But just my opinion.
Good luck!
DL