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INNflight
Topic Author
Posts: 3527
Joined: Tue Apr 13, 2004 5:11 am

"Gear Up" Hight?

Sun May 30, 2004 6:54 pm

Hello,

I just came across this image and in my opinion the gear is retracted way too early?!  Insane


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Photo © Ricardo Morales Aviation Photography of Mexico



Is there any specific hight above ground or something when the gear should be taken up?

thanks, Florian
Jet Visuals
 
star_world
Posts: 943
Joined: Mon Jun 25, 2001 7:52 am

RE: "Gear Up" Hight?

Sun May 30, 2004 7:45 pm

I could be wrong but in that picture, the runway that the a/c took off from isn't actually in the picture, it's nearer the camera? Doesn't look like it took off from the one you can see there, it's just too close to the ground for the wheels to be up already.
 
SUPRAZACHAIR
Posts: 474
Joined: Mon Feb 09, 2004 3:27 pm

RE: "Gear Up" Hight?

Sun May 30, 2004 7:49 pm

In the Arrow and Seminole gear up is when there's no usable runway left. Logic would tell me that in that plane's (or any airliner's) case, V1 will always be before or at Vr, thus once the plane has rotated and left the runway, gear up can happen as soon as the captain feels it is safe. Past V1 the only option for landing is to takeoff and return for landing, so having the gear down is pretty useless. Of course I am not an airline pilot, so this is merely my inference.

Doesn't look like it took off from the one you can see there, it's just too close to the ground for the wheels to be up already.

Again, I'm only speaking from my personal training in small GA aircraft, but gear up is based on usable runway, not height or altitude.


[Edited 2004-05-30 12:54:21]
 
QantasA332
Posts: 1473
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RE: "Gear Up" Hight?

Sun May 30, 2004 8:11 pm

Is there any specific hight above ground or something when the gear should be taken up?

I have read that the gear is usually retracted at around 250-400 ft, but I personally don't think there's really a 'usual', per se. Commercial ops may have a semi-standardized guiding height for retraction, but other than that I think it's really up to the pilot (to a point, of course)...

Cheers,
QantasA332
 
CX Flyboy
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RE: "Gear Up" Hight?

Sun May 30, 2004 8:31 pm

We are required to call "Gear up" when we get positive rate of climb. normally the Pilot Flying calls for it at around 50ft and by the time the PNF checks positive rate, and actually moves the lever, we are at around 100-150ft.
 
Rick767
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RE: "Gear Up" Hight?

Sun May 30, 2004 8:59 pm

As Cx_flyboy said, in airliner operations once a positive climb has been established PF calls for "GEAR UP", and there is no actual standard height for this to occur. In our airline it is PNF who calls "POSITIVE CLIMB", then PF calls for "GEAR UP".

A positive climb is established by both the VSI and the Altimeter, so once the PNF has checked this, made the call, the PF has confirmed it from his instruments / sense check and asked for gear up, and then the PNF has actually moved the gear lever, 100 - 150ft would also be my guess for the gear actually starting to retract.

Useable runway is not a factor for airliner operations like it is for small GA aircraft, when it comes to gear retraction.
I used to love the smell of Jet-A in the morning...
 
PhilSquares
Posts: 3371
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RE: "Gear Up" Hight?

Sun May 30, 2004 9:36 pm

There is no minimum height requirement for gear retraction. Only an indication of positive climb, which is defined as altimeter and IVSI. Once a positive climb is established the PNF calls "POSITIVE CLIMB" and the PNF calls "GEAR UP".

There is no consideration for runway remaining or anything like that. I would say the whole process takes but a few seconds, but most likely the height of the aircraft is 100'-150' or so.
Fly fast, live slow
 
INNflight
Topic Author
Posts: 3527
Joined: Tue Apr 13, 2004 5:11 am

RE: "Gear Up" Hight?

Sun May 30, 2004 10:10 pm

Thank you all for these answers! But still.... look at the image i posted... is it possible they already have "positive climb"?

regards, Florian
Jet Visuals
 
PhilSquares
Posts: 3371
Joined: Sun Mar 28, 2004 6:06 pm

RE: "Gear Up" Hight?

Sun May 30, 2004 10:32 pm

All I would say is the ariplane isn't descending. It looks like a positive climb to me, albeit very shallow.

Fly fast, live slow
 
star_world
Posts: 943
Joined: Mon Jun 25, 2001 7:52 am

RE: "Gear Up" Hight?

Sun May 30, 2004 10:43 pm

I've had a look at some of the other photos taken at this airport... it looks like this aircraft is taking off from runway 05L, but the runway you can see in the picture immediately below it is 05R. This would mean that it's already several hundred feet in the air here, which would be a much more "typical" time for the gear to be raised. Can anyone else who knows this airport well confirm this?
 
pelican
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RE: "Gear Up" Hight?

Sun May 30, 2004 11:25 pm

You have to consider that MEX has an elavation of 7316 Feet (2230 Meters), therefore the initial climb rate can't be very high. So this MD-83 could be in the air for a some seconds.

pelican
 
BritPilot777
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RE: "Gear Up" Height?

Mon May 31, 2004 3:23 am

When I did my Multi in a BE-76 (Duchess) Gear up was when there was no more available runway available. Though this was at an airport with a runway of about 5000ft.

wouldn't really make much sense doing it for a really long runway as the amount of drag would be a lot through your climb out
Forever Flight
 
dl757md
Posts: 1483
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RE: "Gear Up" Hight?

Mon May 31, 2004 5:32 am

I'm not sure, but if you look closely it appears that the shadow of the aircraft is on the runway that is visible indicating that it is indeed taking off from that runway.

[Edited 2004-05-30 22:34:02]
757 Most beautiful airliner in the sky!
 
wilco
Posts: 340
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RE: "Gear Up" Hight?

Mon May 31, 2004 6:24 am

I'm not sure, but if you look closely it appears that the shadow of the aircraft is on the runway that is visible indicating that it is indeed taking off from that runway.

Thats a pretty silly idea.

-WILCO
"Ever seen a grown man naked?"
 
dl757md
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RE: "Gear Up" Hight?

Mon May 31, 2004 6:47 am

Why is that so silly?
757 Most beautiful airliner in the sky!
 
Yikes!
Posts: 358
Joined: Sat Oct 13, 2001 4:51 pm

RE: "Gear Up" Hight?

Mon May 31, 2004 8:43 am

This exact picture/question came up on this forum a few years ago. The resolution was that the aircraft was indeed well into its first segment climb and that the image of what appears to be a runway was either a more distant parallel runway, a taxiway or even an access road.

As has already been stated, in airline operation (which includes aircraft such as Dash 8's), the takeoff segment is terminated when the aircraft has attained a positive rate of climb, is at V2 or better, and has attained a minumum height of 35' AGL. "Positive Rate" or "Positive Climb" is called when, during my employment at 5 different airlines, vertical speed, altimeter and radar altimeter all indicate the aircraft has left the ground and is in a climb. This usually occurs around 20-30' radar altitude. Gear retraction on a large aircraft is a complex procedure of wheel well doors opening, downlocks being broken, the actual retraction, then subsequent closing of extended gear doors. On the 767, from the time of selection "gear up", the process takes about 10-12 seconds. This is a time of high drag and one of the worst places to lose an engine. Not at V1 as most of the world's carriers and regulatory agencies mandate training to be carried out.

I have seen some hotdogs on light and large aircraft alike attempt to raise the gear while either still on the ground, leaving the squat switches to determine when the wheels have left the ground, to one or two individuals who believe that since the nose wheel is off the ground, then the mains must be too.

What a business...

Yikes!
 
wilco
Posts: 340
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RE: "Gear Up" Hight?

Mon May 31, 2004 9:34 am

DI757MD: Except at 12Noon in certain parts of the tropics, the sun is never directly overhead. A lot of the day, morning and late afternoon, the sun is at such an angle that shadows of a flying aircraft are cast hundreds of yards away....

in the pic below, the a/c is departing 26L and the shadow is on 26R

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Photo © Bruce Leibowitz



and more examples:

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Photo © Brian Stevenson - SPOT THIS!



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Photo © Jean



So your statement the shadow of the aircraft is on the runway that is visible indicating that it is indeed taking off from that runway is false.

-WILCO
"Ever seen a grown man naked?"
 
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ghost77
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RE: "Gear Up" Hight?

Mon May 31, 2004 10:05 am

I just came across this image and in my opinion the gear is retracted way too early?!

@ MEx its common to see this kind of depactures with the F100's, Dc9s and MD80s and now AM's 737s, don't know why Azteca's 737 don't suffer while climbing out.

It's common to see AM pilots on the MD80 retracting the gear very soon after departure and fly over the runway very low... and then they continue their climb!

Aircraft was departing runway 05R. It's also important to take into consideration that 05R starts a few meters after 05L. Check your Jeppesen diagrams of MEx!

Local time was around 6:00 p.m. and 6:30 p.m.!

This exact picture/question came up on this forum a few years ago.

Years ago??? Took it on May 14, 2004. Added to DB on May 21st, 2004.

Something else, just throw me your questions!

Ricardo APM  Smile

 
Yikes!
Posts: 358
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RE: "Gear Up" Hight?

Mon May 31, 2004 11:34 am

OK. If not this picture, then a nearly identical picture. Same optical illusion.

Yikes!
 
dl757md
Posts: 1483
Joined: Mon May 24, 2004 9:32 am

RE: "Gear Up" Hight?

Mon May 31, 2004 3:36 pm

OK. If not this picture, then a nearly identical picture. Same optical illusion.


I think Ghost77 is saying that the plane is departing runway 05R which is the runway in the pic and is therefor as INNflight suggested VERY low. No optical illusion.

It's common to see AM pilots on the MD80 retracting the gear very soon after departure and fly over the runway very low... and then they continue their climb!

Aircraft was departing runway 05R. It's also important to take into consideration that 05R starts a few meters after 05L. Check your Jeppesen diagrams of MEx!

757 Most beautiful airliner in the sky!
 
VASI
Posts: 187
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RE: "Gear Up" Hight?

Mon May 31, 2004 7:18 pm

When flying in the jumpseat of a 737-400 some years ago, the FO retracted the gear too early and a warning sound came up. The captain did not gave the order "gear up" as well and was therefore quite angry. A positive rate of climb was established however.

Does someone know something about this accoustic warning, is it also the case in any other type of aircraft?

Thanks!

VASI
 
411A
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RE: "Gear Up" Hight?

Tue Jun 01, 2004 2:04 am

To quote from the PanAmerican B707-320B pilots operating manual...

"Landing gear retraction should be initiated when a sustained positive rate of climb is indicated by the pressure altimeters.

Not the radio altimeter....sloping terrain can give false climb indications. Especially important on very long takeoff runs (heavy weights) where the initial climb is over the clearway/stopway...or beyond.

Not the vertical speed indicator, as it too is subject to climb indication errors just after liftoff. IVSI included.
 
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ghost77
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RE: "Gear Up" Hight?

Tue Jun 01, 2004 3:48 am

As dl757md says; there was no optical illusion., the runway (05R) which is the one visible in the picture, was the one used by this MD on its departure!

Ricardo APM  Smile

 
oklso
Posts: 13
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RE: "Gear Up" Hight?

Wed Jun 02, 2004 2:59 am

Our company procedure mirrors Rick767's. PNF notes positive rate of climb indicated on the IVSI, calls "positive rate." PF confirms on his/her IVSI, calls "positive rate, gear up."
 
Blackbird1331
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RE: "Gear Up" Hight?

Fri Jun 04, 2004 5:26 am

Let's scare the pants off the boss.


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Photo © Paul Robinson

Cameras shoot pictures. Guns shoot people. They have the guns.
 
cancidas
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RE: "Gear Up" Hight?

Fri Jun 04, 2004 1:49 pm

We are required to call "Gear up" when we get positive rate of climb.

that's the way i was tought to fly airplanes with retractable gear. most airlines state when to retract in thier ops specs though.
"...cannot the kingdom of salvation take me home."
 
SUPRAZACHAIR
Posts: 474
Joined: Mon Feb 09, 2004 3:27 pm

RE: "Gear Up" Hight?

Fri Jun 04, 2004 3:46 pm

that's the way i was tought to fly airplanes with retractable gear. most airlines state when to retract in thier ops specs though.

Except that puts you in a pickle when your Arrow loses power 50-100AGL on a longer (5-6000ft) runway. Although you may have attained a positive rate, you're in trouble if you're engine sputs out at this point and you're gear is only starting to go up. If you wait until you have no more usable runway before retracting the gear then you're assured the gear will be down in case you're forced to put the plane back onto the runway. Just a thought.
 
cancidas
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RE: "Gear Up" Hight?

Sat Jun 05, 2004 1:30 am

Except that puts you in a pickle when your Arrow loses power 50-100AGL on a longer (5-6000ft) runway. Although you may have attained a positive rate, you're in trouble if you're engine sputs out at this point and you're gear is only starting to go up. If you wait until you have no more usable runway before retracting the gear then you're assured the gear will be down in case you're forced to put the plane back onto the runway. Just a thought.

that's what an engine run-up is for, to root out those kind of problems.
"...cannot the kingdom of salvation take me home."
 
avt007
Posts: 1989
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RE: "Gear Up" Hight?

Sat Jun 05, 2004 3:12 am

During WWII, some hot dog Spitfire pilots would select gear up on the takeoff roll, so that upon liftoff, the gear would immediately retract, for a show-off type departure. Unfortunately, given that grass fields were the norm, a slight bump or undulation in the ground would also cause the gear to retract, leaving the aircraft to settle to the ground, leaving the highly embarrassed pilot to deal with the CO.
 
SUPRAZACHAIR
Posts: 474
Joined: Mon Feb 09, 2004 3:27 pm

RE: "Gear Up" Hight?

Sat Jun 05, 2004 3:59 am

that's what an engine run-up is for, to root out those kind of problems.

Well, if you're content with that reasoning, then thats your prerogative. I like to adhere to old adage "expect the unexpected". Engine failures do happen on climb out, even after a run up is done. ALWAYS leave yourself an out. I'll personally hold onto that usable runway as my possible out in the rare situation that my engine craps out.
 
411A
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RE: "Gear Up" Hight?

Sat Jun 05, 2004 9:35 am

SupraZachAir,

You are wise beyond your years.
Experienced pilots ALWAYS leave themselves an alternative, for when Murphys law strikes, it can catch you out, unless you are prepared.

Then, it's...hello FAA (or CAA, RLD, LBA, DGCA, etc.)
Un-prepared is BAD.

Remember, the 6 P's.

For those that don't know...prior planning prevents pi** poor performance.
 
XFSUgimpLB41X
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RE: "Gear Up" Hight?

Sat Jun 05, 2004 10:03 am

FYI...was kinda eyeballings what altitude i actually sucked the gear up in my little barbie jet this last trip...

Pretty much everytime I would be able to confirm, grab the lever and say "Yes oh great,wise, wonderful, and almighty captain, I shall raise your landing gear at this time!!" was about 100 feet or slightly higher.
Chicks dig winglets.
 
waketurbulence
Posts: 1264
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RE: "Gear Up" Hight?

Mon Jun 07, 2004 10:27 am

I feel that there is nothing dangerous or wrong about this picture. Although it is not common, gear is sometimes retracted at this height. Just because gear isn't retracted this way most the time does not mean it is a bad thing. I wish I could post some videos I have of many a/c that take off like this. Here is one discussion I found related to this topic.
https://www.airliners.net/discussions/tech_ops/read.main/79316/4/
-Matt

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