Do some 737s have built in airstairs? I thought DC-9s and 727s etc had them.

MyAviation.net photo:

Photo © Martin Jakobsen

You just posted a picture of one! The answer is yes. Some A320's have them too. There was a thread about this not too long ago, but I couldn't find it in the search. You don't hear much about them because of the proliferation of Jetways, and most are inoperable because the airliners choose not to maintain them (weight, money etc.).

Quoting 727EMflyer (Reply 1): most are inoperable because the airliners choose not to maintain them (weight, money etc.).

Not just inoperable, but in most cases not installed at the factory. The space exists, the hard points and possible even wiring may be there, but the whole structure was left out.

Exception of course would be for those customers who know they are going to places without jetways, possibly even without boarding stairs.

Yes, depends if the airline spec'd for them.

Actually on the 737 there is the forward door that you see there, and then on combi aircraft there can be a door on the rear exit.

The doors function differently too. The one at the rear, the door is hindged at the bottom to form the top flight of stairs. As you can see on the forward door, it folds up and then retracts into the airframe below the door.

Quoting L-188 (Reply 3): Actually on the 737 there is the forward door that you see there, and then on combi aircraft there can be a door on the rear exit.

Unnecessary Complications in todays era.
 

We used to have a lot of problems with the Sequencing circuit.
regds
MEL

Quoting HAWK21M (Reply 4): We used to have a lot of problems with the Sequencing circuit.

Mel For what purpose is the sequencing circuit used there? Also where are the controls for extending and retracting the airstairs situated?

Regards
George

The Airstair on a B737 can be operated from Outside & from Inside provided Entry door is open by using 28vdc or 115vac.
There are Two optng systems involved Normal & Standby.
Standby is dc operated & has not safety swiches on the Handrails,hence if the Handrails are not stored properly it can lead to damage during retraction of the Airstair.
The Sequences involve Position/limit/sequence switches than allow each step to occur in sequence,starting from opening of the Airstair door to Extending of the Airstair.
The outside controls are below aft of the Air stair opening & the Inside control is above the Entry door cutout.
regds
MEL

The question was asked some months ago, so I tried to snap a picture of those stairs being retracted :

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Photo © Antoine Ossadzow

As stated 737's have them installed during initial build, only if the customer requests. The 737 I maintain did not have them as original equip., so we went to the desert and found us a set and installed them. I know 717 have all the provisions for them, it just differed as to the customer wanting to take on the additional wt. penalties of the installed equipment. Some carriers have them, but choose to deactivate them.

Well here we go a photo of the rear airstair.

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Photo © Brian Hames

Quoting HAWK21M (Reply 4): Unnecessary Complications in todays era.

If may be complicated but I am sure in your neck of the woods there are places where having a plane that support itself is kind of handy.


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Photo © Tony Solis

You may find some more answers here:
http://www.airliners.net/discussions...eral_aviation/read.main/1957575/6/

Why are the doors cracked as the stairs are being lowered?

Thanks,
AAndrew

Aa757first,

Would you want even the possibilty of a flight if they were not properly stowed prior to door closure? I'm speaking DC9 series stowing of the airstairs, it's just my guess, and I can't speak with regards to the 737.

Mike

This is the Airbus compartment

A321- Chute compartment - the black square under number 2 door.

View Large View Medium Photo © R.Hesse

View Large View Medium Photo © Daniel Klein

View Large View Medium Photo © R.Hesse

View Large View Medium Photo © R.Hesse

Tom.

Technically no, but I do recall the BP and ARCO birds had them, Those where the airplanes owned by the oil companies that at the time Alaska provided the mx and ground support for.

I don't believe the -400's had them either, at least a few of the MD-80's did.

As far as the NG aircraft, those are before my time.

The 37's have sequencing too. Can not open/close airstairs unless L-1 door open. However you can with ground control handle.