slinker
Posts: 16
Joined: Mon Feb 27, 2006 5:15 am

Why The "wheel" On Landing Gear Levers?

Fri Mar 03, 2006 7:52 pm

I've always wondered why the levers for landing gear in commercial airliners usually have a wheel on the end of them (instead of just being a toggle switch or something like that). Anyone care to enlighten me?

Thanks!
 
David L
Posts: 8547
Joined: Tue May 18, 1999 2:26 am

RE: Why The "wheel" On Landing Gear Levers?

Fri Mar 03, 2006 8:13 pm

As a visual and tactile cue to reduce the chance of pulling the wrong lever, I believe.
 
EMBQA
Posts: 7795
Joined: Sat Oct 25, 2003 3:52 am

RE: Why The "wheel" On Landing Gear Levers?

Fri Mar 03, 2006 8:17 pm

As said above....For the same reason a flap handle looks and feels like a flap.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
bphendri
Posts: 136
Joined: Fri Mar 03, 2006 3:18 am

RE: Why The "wheel" On Landing Gear Levers?

Fri Mar 03, 2006 10:28 pm

Darn, I was going to say the same thing, but you guys beat me to it  Sad
 
Sinlock
Posts: 1631
Joined: Fri Dec 22, 2000 12:55 am

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 12:00 am

It's a carry over from the day when aircraft had more levers in the cockpit.

It was standard and in many cases an Federal Aviation Regulation that different controls ended with a different shape handle so during reduced visibility such as darkness or smoke that the pilots could determine the type of control by feel. Different manufactures used different shapes and color for Throttle, Prop Pitch, Mixture, Turbo/Supercharger. The same thing is done for Lights, Flaps and Trim.


View Large View Medium
Click here for bigger photo!

Photo © Alex McMahon



View Large View Medium
Click here for bigger photo!

Photo © Yasir Raja



View Large View Medium
Click here for bigger photo!

Photo © Suresh A. Atapattu



View Large View Medium
Click here for bigger photo!

Photo © AirNikon



View Large View Medium
Click here for bigger photo!

Photo © Dmitry Avdeev

 
aogdesk
Posts: 748
Joined: Wed Jun 09, 2004 2:26 am

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 12:04 am

And it definitely works. After some time of being familiarized with the cockpit, you can close your eyes and find almost every lever, switch, handle, etc.
 
ilikeyyc
Posts: 1326
Joined: Tue Dec 09, 2003 8:09 am

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 8:02 am

I believe the rule resulted from several crashes of Beech 18's which, at the time, had the flap and gear levers in close proximity to eachother and looked exactly alike.
Fighting Absurdity with Absurdity!
 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 10:27 am

We covered some of this quite a few years ago...The 1950s really started some human factors input in to aircraft design. Boeing, for example, would even make switch position (off/on) on the overhead of the 727 airline specific...Later, standards started to develop...to include the Boeing philosophy of electrical on the left over head, fuel left center, lights above the glareshield, hydraulics/bleeds/pneumatics over the FO...
 
User avatar
zeke
Posts: 9757
Joined: Thu Dec 14, 2006 1:42 pm

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 12:40 pm

Quoting David L (Reply 1):
As a visual and tactile cue to reduce the chance of pulling the wrong lever, I believe.

Also for smoke in the cockpit, you may not be able to see it, but you can feel it.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
Buzz
Posts: 694
Joined: Sun Nov 21, 1999 11:44 pm

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 2:20 pm

Hi Slinker, Buzz here. Besides what the other guys have said about being a good human-factors idea, it's required in FAR 25.
I forget the sub part, but there's a page that shows what shape each control is supposed to be: Landing Gear, Throttle, Prop, Mixture.
The DC-3 was certified under CAR 3 (or was it CAR 4?) and it's been grandfathered so you don't have to replace the knobs. They're all round. But they come in different colors to help you grab the right one.
g'day
 
andz
Posts: 7624
Joined: Mon Feb 16, 2004 7:49 pm

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 4:14 pm

Look at all these levers! And maybe a 747 should have one of these anti-gear up straps  Wink


View Large View Medium
Click here for bigger photo!

Photo © Julian Whitelaw

After Monday and Tuesday even the calendar says WTF...
 
slinker
Posts: 16
Joined: Mon Feb 27, 2006 5:15 am

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 5:15 pm

Thanks - you guys rock. I think it's great that I had a question pop into my head, posted it, and got terrific answers in a matter of hours.

Thanks again,
Seth
 
David L
Posts: 8547
Joined: Tue May 18, 1999 2:26 am

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 6:52 pm

Quoting Zeke (Reply 8):
Quoting David L (Reply 1):
As a visual and tactile cue to reduce the chance of pulling the wrong lever, I believe.

Also for smoke in the cockpit, you may not be able to see it, but you can feel it.

That would be the "tactile cue" part.  duck 
 
ZKSUJ
Posts: 6806
Joined: Tue May 18, 2004 5:15 pm

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 6:55 pm

As mentioned above. Its a cockpit design/ergonomics/human factors thing as far as i know.
 
fr8mech
Posts: 6595
Joined: Mon Sep 26, 2005 9:00 am

RE: Why The "wheel" On Landing Gear Levers?

Sat Mar 04, 2006 10:50 pm

Quoting Andz (Reply 10):
And maybe a 747 should have one of these anti-gear up straps

It does. It has a little gate that prevents handle movement while on the ground.
When seconds count...the police are minutes away.
 
Argonaut
Posts: 142
Joined: Thu Dec 30, 2004 3:17 am

RE: Why The "wheel" On Landing Gear Levers?

Sun Mar 05, 2006 3:19 am

On a cockpit visit many years ago, a B727 F/E told me it had a wheel on it because pilots were not very intelligent.  rotfl 

His colleagues up front didn't appear to disagree with him.
'the rank is but the guinea stamp'
 
citationjet
Posts: 2251
Joined: Sun Mar 09, 2003 2:26 am

RE: Why The "wheel" On Landing Gear Levers?

Sun Mar 05, 2006 4:04 am

Quoting Buzz (Reply 9):
it's required in FAR 25.
I forget the sub part, but there's a page that shows what shape each control is supposed to be: Landing Gear, Throttle, Prop, Mixture.

FAR 25.781 Cockpit Control Knob Shape

http://www.airweb.faa.gov/REGULATORY...2143585256672005114C3?OpenDocument

.
Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,737,738,739;741,742,743,744,747SP;752,753;762,763;772,773.
 
David L
Posts: 8547
Joined: Tue May 18, 1999 2:26 am

RE: Why The "wheel" On Landing Gear Levers?

Sun Mar 05, 2006 4:57 am

Completely irrelevant but... is the wheel free to spin? One could annoy the hell out of one's flight-deck colleague(s) if it is.  Smile
 
AmericanAirFan
Posts: 385
Joined: Mon Jun 28, 2004 10:22 am

RE: Why The "wheel" On Landing Gear Levers?

Sun Mar 05, 2006 6:10 am

Quoting David L (Reply 17):
Completely irrelevant but... is the wheel free to spin? One could annoy the hell out of one's flight-deck colleague(s) if it is. Smile

Nope it's just part of the lever at the end  Smile
"American 1881 Cleared For Takeoff One Seven Left"
 
David L
Posts: 8547
Joined: Tue May 18, 1999 2:26 am

RE: Why The "wheel" On Landing Gear Levers?

Sun Mar 05, 2006 7:27 am

Quoting AmericanAirFan (Reply 18):
Nope it's just part of the lever at the end

Oh well, I guess there's always the retractable ballpoint pen.  Smile
 
satx
Posts: 2771
Joined: Mon Apr 11, 2005 7:26 am

RE: Why The "wheel" On Landing Gear Levers?

Sun Mar 05, 2006 9:35 pm

Quoting David L (Reply 19):
Oh well, I guess there's always the retractable ballpoint pen.

I think someone needs to design an actual inflatable spinning wheel for the end. You could spin it and let out the air and then move the flaccid tube around and then pump it up with air again and go back to spinning it.  Big grin
Open Season on Consumer Protections is Just Around the Corner...
 
amtrosie
Posts: 273
Joined: Thu Jan 06, 2005 6:44 am

RE: Why The "wheel" On Landing Gear Levers?

Sun Mar 05, 2006 11:56 pm

Quoting Argonaut (Reply 15):
because pilots were not very intelligent.

His colleagues up front didn't appear to disagree with him

Which is why I refer to our pilots as the "lumps in the right seat or left seat". Our f/o does not care for the characterization, but as "the boulder" (the unmovable source) I have the last say.

Quoting David L (Reply 19):
Quoting AmericanAirFan (Reply 18):
Nope it's just part of the lever at the end

Oh well, I guess there's always the retractable ballpoint pen.

On one of our planes we had a switch which was to NOTHING. We refer to it as the "diddle" switch. It's sole function is to allow the "lumps" to diddle with it as opposed to a real switch, thus not breaking something of importance when they are bored.
 
IFACN
Posts: 149
Joined: Sun Nov 20, 2005 7:14 am

RE: Why The "wheel" On Landing Gear Levers?

Mon Mar 06, 2006 2:27 am

Quoting Amtrosie (Reply 21):
we had a switch which was to NOTHING. It's sole function is to allow the "lumps" to diddle with it as opposed to a real switch, thus not breaking something of importance when they are bored.

As per the current regulations, can it be operated under 10'000 ft or boredom is banned in a 'sterile cockpit' environment?  Silly

By the way, let me know which airline you work for so I'll book my future flight with someone else. See, I'd be very disappointed if the last things I hear in my life are "yawn - click click - yawn - click click - crash!" Big grin

Regards,
A.
 
citationjet
Posts: 2251
Joined: Sun Mar 09, 2003 2:26 am

RE: Why The "wheel" On Landing Gear Levers?

Mon Mar 06, 2006 2:46 am

I have heard of a Gulfstream operator that added a buzzer to the cockpit instrument panel that goes off every so many minutes, and the pilot has to turn it off. The goal is to keep the crew awake and alert.
Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,737,738,739;741,742,743,744,747SP;752,753;762,763;772,773.
 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: Why The "wheel" On Landing Gear Levers?

Mon Mar 06, 2006 2:56 am

Quoting CitationJet (Reply 23):
I have heard of a Gulfstream operator that added a buzzer to the cockpit instrument panel that goes off every so many minutes, and the pilot has to turn it off. The goal is to keep the crew awake and alert.

I've know most modern locomotives have a deadman switch, but never heard of a Gulfstream. Usually there's enough interaction with ATC to preclude that need.
 
TEBGuy
Posts: 237
Joined: Thu Feb 03, 2005 6:26 am

RE: Why The "wheel" On Landing Gear Levers?

Mon Mar 06, 2006 12:50 pm

Quoting Amtrosie (Reply 21):
On one of our planes we had a switch which was to NOTHING. We refer to it as the "diddle" switch. It's sole function is to allow the "lumps" to diddle with it as opposed to a real switch, thus not breaking something of importance when they are bored.

I take it this was a switch from something that was deactivated? what had it been for?
Remember, taking off is optional, landing is mandatory.
 
David L
Posts: 8547
Joined: Tue May 18, 1999 2:26 am

RE: Why The "wheel" On Landing Gear Levers?

Mon Mar 06, 2006 10:06 pm

Quoting Amtrosie (Reply 21):
On one of our planes we had a switch which was to NOTHING. We refer to it as the "diddle" switch. It's sole function is to allow the "lumps" to diddle with it as opposed to a real switch, thus not breaking something of importance when they are bored.

I like that... flicking the switch to and fro while thinking "I'm flying the plane!".

Quoting IFACN (Reply 22):
See, I'd be very disappointed if the last things I hear in my life are "yawn - click click - yawn - click click - crash!"

 biggrin 
 
amtrosie
Posts: 273
Joined: Thu Jan 06, 2005 6:44 am

RE: Why The "wheel" On Landing Gear Levers?

Sun Mar 12, 2006 7:43 am

Quoting TEBguy (Reply 25):
I take it this was a switch from something that was deactivated? what had it been for?

Not sure what its original function was, but it sure prevented them from breaking something that was needed.

Quoting IFACN (Reply 22):
As per the current regulations, can it be operated under 10'000 ft or boredom is banned in a 'sterile cockpit' environment?

By the way, let me know which airline you work for so I'll book my future flight with someone else. See, I'd be very disappointed if the last things I hear in my life are "yawn - click click - yawn - click click - crash!"




Sterile cockpit rules definately do apply. We dare not get sloppy with cockpit protocal!!!

This switch was on our Gulfstream, and we are considering putting one in our other aircraft. You need not worry about flying with us, no intelligent life forms allowed on board!!  laughing  That is why I will not fly, nor my dog!!
 
User avatar
HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Why The "wheel" On Landing Gear Levers?

Thu Jan 04, 2007 2:57 pm

Symbolism......Resembles the Control used.Noticed the Flap lever  Smile at least on B737 & B757.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Stealthz
Posts: 5546
Joined: Wed Feb 02, 2005 11:43 am

RE: Why The "wheel" On Landing Gear Levers?

Thu Jan 04, 2007 5:59 pm

Quoting CitationJet (Reply 23):
I have heard of a Gulfstream operator that added a buzzer to the cockpit instrument panel that goes off every so many minutes, and the pilot has to turn it off. The goal is to keep the crew awake and alert.



Quoting EssentialPowr (Reply 24):
I've know most modern locomotives have a deadman switch, but never heard of a Gulfstream.

Perfect for the multi modal transport conglomerate, cross qualify your EMD SD70M & GE AC4400 engineers to fly the G-V as well..!!
Hope the Gulfstream "deadmans" buzzer doesn't apply brakes and shutdown the aircraft if not responded to!
If your camera sends text messages, that could explain why your photos are rubbish!
 
ThirtyEcho
Posts: 1409
Joined: Tue Jan 01, 2002 1:21 am

RE: Why The "wheel" On Landing Gear Levers?

Thu Jan 04, 2007 6:02 pm

Recip pilots have some real advantages, here. You can irritate others by constatantly fooling with mixture, synchrophaser, fuel flow, prop pitch, CHT, cowl flaps and the rest of the endless list.

Or just hand fly the airplane and constantly bobble pitch trim.
 
BAE146QT
Posts: 981
Joined: Sun Sep 24, 2006 4:58 am

RE: Why The "wheel" On Landing Gear Levers?

Thu Jan 04, 2007 9:08 pm

Quoting Amtrosie:
On one of our planes we had a switch which was to NOTHING. We refer to it as the "diddle" switch. It's sole function is to allow the "lumps" to diddle with it as opposed to a real switch, thus not breaking something of importance when they are bored.

Such things are not always harmless or benign however;

I refer you to the following story;

http://www.livingstonmontana.com/access/dan/191magicswitch.html

:::EDIT::: Dang it MEL! You've gone and done it again, you little tinker.

[Edited 2007-01-04 13:09:28]
Todos mis dominós son totalmente pegajosos
 
DH106
Posts: 592
Joined: Wed Jun 15, 2005 5:32 pm

RE: Why The "wheel" On Landing Gear Levers?

Thu Jan 04, 2007 9:30 pm

Quoting Andz (Reply 10):
Look at all these levers! And maybe a 747 should have one of these anti-gear up straps

Just out of interest - how does that red strap attached to the overhead panel in the DC-4 prevent gear retraction? Doesn't look like the lower end is attached to the gear lever - in any case it wouldn't stop the gear lever moving up !  Smile Is there an additional baulk which the strap attaches on the floor?
...I watched c-beams glitter in the dark near the Tanhauser Gate....
 
User avatar
HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Why The "wheel" On Landing Gear Levers?

Thu Sep 06, 2007 11:04 pm

Quoting DH106 (Reply 32):
how does that red strap attached to the overhead panel in the DC-4 prevent gear retraction

Anyone aware of the Answer.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
User avatar
Jetlagged
Posts: 2562
Joined: Sun Jan 23, 2005 3:00 pm

RE: Why The "wheel" On Landing Gear Levers?

Fri Sep 07, 2007 12:41 am


View Large View Medium
Click here for bigger photo!

Photo © Julian Whitelaw


The strap stops the big red lever on the left being moved aft, which I guess would release the downlocks.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
737tdi
Posts: 1116
Joined: Sun Sep 02, 2007 10:05 am

RE: Why The "wheel" On Landing Gear Levers?

Fri Sep 07, 2007 1:18 am

To add something to this, the original poster asked "why not just a toggle switch?" On the aircraft I have worked, the landing gear handle is considered a control, (aileron, flap, rudder control as an example). None of the ones I've worked being fly by wire (except the F-18). The landing gear handle and emergency extend handle are cable operated, thus why it can not be an electrical type switch.

737tdi
 
User avatar
Jetlagged
Posts: 2562
Joined: Sun Jan 23, 2005 3:00 pm

RE: Why The "wheel" On Landing Gear Levers?

Fri Sep 07, 2007 6:19 am

Quoting 737tdi (Reply 35):
To add something to this, the original poster asked "why not just a toggle switch?" On the aircraft I have worked, the landing gear handle is considered a control, (aileron, flap, rudder control as an example). None of the ones I've worked being fly by wire (except the F-18). The landing gear handle and emergency extend handle are cable operated, thus why it can not be an electrical type switch.

The landing gear lever is considered to be a secondary flight control, as you say. Traditionally the gear lever is connected by cable to the selector valve which ports the pressure to the system. Hence it is large and moves through a considerable arc. However they can be electrically signalled rather than cable operated. Even so the levers still have the wheel shapes on the end. The Airbus is a good example of this.

Some military aircraft do just have pushbuttons to control the gear. Most fighters don't have room for large control levers in the cockpit.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
Viscount724
Posts: 18846
Joined: Thu Oct 12, 2006 7:32 pm

RE: Why The "wheel" On Landing Gear Levers?

Fri Sep 07, 2007 12:35 pm

On a somewhat related issue, I recall reading quite a few years ago that there was a difference of opinion whether toggle switches should be up (or forward if mounted horizontally) when "on" (like light switches on the wall) and down (or to the rear if horizontal) when "off", or vice versa, and that some aircraft or airlines had switches that worked in opposite directions from others due to their policy on the issue (or perhaps the policy of the regulatory authorities in the country concerned).

I forget the details but is any of this still an issue or is there now a standard for the on/off positions of toggle switches? It would seem to create serious safety issues if pilots moved from one airline to another if switches worked in the opposite direction to what they were familiar with. Or have toggle switches mostly been replaced with rotating knobs where "on" is presumably clockwise and "off" counterclockwise?
 
User avatar
Jetlagged
Posts: 2562
Joined: Sun Jan 23, 2005 3:00 pm

RE: Why The "wheel" On Landing Gear Levers?

Sat Sep 08, 2007 12:22 am

Quoting Viscount724 (Reply 37):
Or have toggle switches mostly been replaced with rotating knobs where "on" is presumably clockwise and "off" counterclockwise?

Toggle switches are alive and well. As is the up/down for ON controversy! The down/forward for ON seems to be favoured in the USA, where ironically domestic light and power switches are up for ON. In Europe it tends to be up/aft for ON in the aircraft and down for ON in the home. C'est la vie.

Embraer have adopted a convention on their flightdecks where rotary selectors are vertical in the normal position. This seems to be a general rule elsewhere too, but there are probably exceptions.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
User avatar
HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Why The "wheel" On Landing Gear Levers?

Sat Sep 08, 2007 4:44 am

I remember on the B737s some operators used to locate the Hyd pumps toggle sw posn as On on top & off below while some stuck to Off on top & on below.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
CoolGuy
Posts: 366
Joined: Tue Jan 18, 2005 8:13 am

RE: Why The "wheel" On Landing Gear Levers?

Tue Sep 11, 2007 12:51 am

Just wondering, what happens if the lever is moved at an inappropriate time, i.e. pulled up on the ground or down at cruise speed/altitude?
 
User avatar
HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Why The "wheel" On Landing Gear Levers?

Tue Sep 11, 2007 5:40 pm



The lever is in the off position in cruise.Its the Depressurised position where only the Mechanical uplocks with bungee springs assist in keeping the Gear up.

On Ground.The lever cannot be moved to up due to an Air-Grd interlock.This can be overridden though.In order to check the Upline for leaks,place all the L/G ground lock pins in position & then cycle the lever with Hydraulics available.

The up position is used only during retraction & after ensuring the gear is up & Locked,the lever is moved to Off position.

The Down position is mechanicaly locked in place on ground unless overridden.

regds
MEL
I may not win often, but I damn well never lose!!! ;)

Who is online

Users browsing this forum: No registered users and 8 guests