Master Caution & Gear Disagree

[PJ2]

I am hoping someone can answer this definitevly, from experience or with specific references either from the FCOM or AMM:

On a B737-400, will the Master Caution light come ON with any of the gear disagree lights ON?

[Jim_12]

It will not come on. The only indication will be illumination of any of the applicable red/green lights above the gear handle.

[PJ2]

Hi Jim_12;

Thanks for your response. I have heard that and know the reasons why the MC probably doesn't come on - (is designed to only come on to draw attention to cautions or warnings not in direct view of the crew). But I need something definitive which is a bit more difficult as it is "stating a negative". I've looked in the AMM for MC conditions and the gear isn't listed so that's probably the most definitive - I'm just needing confirmation from others and your response helps.

[FlightDetent]

PJ2, someone other will need to give you the definitive answer.

Looking back at my notes I both see and remember that MC with associated Recall / Sys Indication press-pad only served for failures from the overhead panel.

L/G lights are in forward field of vision hence they wouldn't be covered.

Standing by for someone with active knowledge...

PS: Here's some text retrieved from Sys description of Warning system taken from SmartCockpit website.

Master Caution Lights
Two MASTER CAUTION lights illuminate when any caution occurs outside the normal field of vision of the flight crew. The lights remain illuminated as long as the caution condition exists, or until the crew resets the system. Pushing either MASTER CAUTION light extinguishes both lights and resets the master caution system for further cautions. Pushing either annunciator light panel recalls all existing fault annunciations.
A single fault in certain redundant systems--or some simple faults--do not illuminate the MASTER CAUTION or system annunciator lights. These faults, however, are stored in the master caution system. Pushing the system annunciator recalls the single fault on the system annunciator panel.

[FlightDetent]

Crossed posts. But more from the FCOM:

Landing Gear Configuration Warnings
Visual indications and aural warnings of landing gear position are provided by the
landing gear indicator lights and landing gear warning horn.
Visual Indications
The landing gear indication lights are activated by signals from each gear, the
LANDING GEAR lever, and the forward thrust lever position as follows:
Green light illuminated – landing gear is down and locked.
Red light illuminated –
• landing gear is in disagreement with LANDING GEAR lever position (in
transit or unsafe).
• landing gear is not down and locked--with either or both forward thrust
levers retarded to idle.
All lights extinguished – landing gear is up and locked with the LANDING GEAR
lever UP or OFF.

Found it here: B737E Warning Systems

[PJ2]

Thank you FLIGHTDETENT - I have the B737-400 FCOM & AMM - just trying to get an air-tight answer - I strongly suspect the MC does not come on but I need to know for sure.

[PJ2]

Another question...if the gear were oversped while being extended, down or being retracted, would the MC come on?

[Jim_12]

Unless your aircraft is equipped with an AFIRS or other reporting system there will be no indication to you or your operations of a gear or flap over speed.

[Denti]

No warning for gear overspeed at all. It should be discovered during the routine flight data analysis. To fly too fast for an extended gear however is probably a very rare occurrence, the sound close to the max extended speed gets deafening, even with ANR headsets, however overspeeding during retraction probably can happen, extension only with a very, hmm, stupid, mistake.

[PJ2]

Thanks Denti, appreciated. It's a matter of certainty as you may sense from the original question. In reading carefully have found that conclusions may be only inferred from the FCOM and AMM and as such, the conclusions are logical in the normal way. I need something from someone who knows the airplane thoroughly and from a technical p.o.v.

[gusting_45]

Only gear anomaly I had was 3 greens and 3 reds simultaneously. No master caution.

[PJ2]

That pretty well cinches it gusting_45, thanks.

[c100driver]

If you had three reds and three greens then the most likely issue is the microswitch in the landing gear handle is not made. Long time B733 pilots always bump the gear lever in after placing the gear down to ensure the micro switch is made. Easy to see what it looks like is to pull the landing gear handle out about a 1/4 inch when it is down and you will get the reds and the greens. Just push the handle in it goes back to three greens.

The MC in the classic is not connected to the landing gear lever indications as the warning lights are in the pilot field of view.

Chapter 15 in FCOM2 The warnings section list the related systems and amber lights that activate the MC.

The blurb from the FCOM.

Two Master Caution lights illuminate when any caution occurs outside the normal field of vision of the flight crew.

[gusting_45]

All those thousands of hours flying various boeings and I never thought of that, well I never.

Just as well I went around anyway, to be sure.