Simple question really. Why is there an LE Transit/Extend light on the 737? What is the impotance of this light? Shouldn't it be obvious when I change my flap settings to anything but 0? 

By all means, roast me for my lack of knowledge on leading edges because I really don't know their purpose. Thanks for answering my question!

Simple answer....it let's you know that the leading edge slats are moving into position.  You can always verify that by looking out your window at the leading edge of the wing.  Just like the oil warning light on your car lets you know your oil level is low.

Just now, charliearon said:

Simple answer....it let's you know that the leading edge slats are moving into position.  You can always verify that by looking out your window at the leading edge of the wing.  Just like the oil warning light on your car lets you know your oil level is low.

Is there a really a reason for the light though? Is there something that commonly can wrong with it or is it just an extra layer of warning/protection/notification for the pilots? It's just weird to me that there's an orange light just for the edge of the wing moving into position. 🤔

The only thing i can think of is the black box acting as an event recorder for deployment in case the plane crashes. Since everything is interconnected, investigators can look at data.

Edited November 7, 20196 yr by Paul Deluca

31 minutes ago, ClaytonYosten said:

Is there a really a reason for the light though? Is there something that commonly can wrong with it or is it just an extra layer of warning/protection/notification for the pilots? It's just weird to me that there's an orange light just for the edge of the wing moving into position. 🤔

I would call them "confidence" lights.  It just gives you an extra something to verify you did your task.  Now something like the landing gear lights are more critical because you can't stick your head out of the window to make sure they are down or up!

A possible use.. The light goes out if fully extended or retracted.
It can show a malfunction in the slat system if the light doesn't go out.
Leading to possible unbalanced lift from the wings.
The slats are somewhat segmented, you cannot see the inner section from the cockpit.

Simply speaking, It lights up whenever LE not align with TE

Aligned : Retracted for Up, Half extented for 1-5(or 1-25 for SFP) and Full extented for more.

So it would come up Both when in transition or some failure.

7 hours ago, ClaytonYosten said:

Is there something that commonly can wrong with it or is it just an extra layer of warning/protection/notification for the pilots? 

The slats are aerodynamically more important than the flaps and the LE transit lights are also essential if there's a slat asymmetry.

Since the slats position indication is on the aft part of the overhead panel where you really don't need it, and the flaps indicator only indicates the trailing edge flaps, the transit lights are essantial.

On more modern Boeings the LE/TE transit/asymmetry etc. is depicted on the EICAS.

Interestingly the LE transit lights on the 737 are disabled when the auto slat system is active.

Edited November 8, 20196 yr by FDEdev

1 hour ago, FDEdev said:

The slats are aerodynamically more important than the flaps and the LE transit lights are also essential if there's a slat asymmetry.

Since the slats position indication is on the aft part of the overhead panel where you really don't need it, and the flaps indicator only indicates the trailing edge flaps, the transit lights are essantial.

On more modern Boeings the LE/TE transit/asymmetry etc. is depicted on the EICAS.

Interestingly the LE transit lights on the 737 are disabled when the auto slat system is active.

You would think they would just be on the EICAS for the 737 but I'm no expert.

 

Thanks for all of the responses, by the way.

Clay