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Landing Gear Placard Limit  
User currently offlinesmartt1982 From United Kingdom, joined Nov 2007, 225 posts, RR: 0
Posted (1 year 10 months 3 weeks 3 days 18 hours ago) and read 5722 times:

On the landing Gear limit speed placard on our aircraft it says 270 -.82M. Would I need to be at a speed below both of these or just one. Thinking of a case if I was 285 knots indicated but only .69M etc.

Would I just whatever one I was using as a reference at that time?

29 replies: All unread, showing first 25:
 
User currently offlineFabo From Slovakia, joined Aug 2005, 1219 posts, RR: 1
Reply 1, posted (1 year 10 months 3 weeks 3 days 18 hours ago) and read 5707 times:

under both.

filler filler



The light at the end of tunnel turn out to be a lighted sing saying NO EXIT
User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 2, posted (1 year 10 months 2 weeks 3 days 7 hours ago) and read 5268 times:

That is the range.........Not to exceed BOTH.


Think of the brighter side!
User currently offlinebueb0g From United Kingdom, joined Jul 2010, 642 posts, RR: 0
Reply 3, posted (1 year 10 months 2 weeks 3 days 6 hours ago) and read 5253 times:

Quoting HAWK21M (Reply 2):
That is the range.........Not to exceed BOTH.

You mean not to exceed either?



Roger roger, what's our vector, victor?
User currently offlinebarney captain From United States of America, joined Nov 2001, 938 posts, RR: 13
Reply 4, posted (1 year 10 months 2 weeks 3 days 5 hours ago) and read 5237 times:

So - you FLY the aircraft, yet don't understand the placard speed - is that correct?


...from the Banana Republic....
User currently offlinetb727 From United States of America, joined Jun 2005, 1588 posts, RR: 9
Reply 5, posted (1 year 10 months 2 weeks 2 days 22 hours ago) and read 5159 times:

Well there is one thing you can count on, it's gonna be loud at high speed.


Too lazy to work, too scared to steal!
User currently offlineRoseflyer From United States of America, joined Feb 2004, 9610 posts, RR: 52
Reply 6, posted (1 year 10 months 2 weeks 2 days 22 hours ago) and read 5153 times:

Usually you have 4 speeds for landing gear. A maximum speed for extension in Mach. A maximum speed for extension in Knots. A maximum gear extended speed in Mach. A maximum gear extended speed in Knots. Exceeding any limit requires a landing gear inspection.

I have been on an airplane exceeding the gear extended speed and the buffet is extreme. It is loud and the airplane is shaking violently (in buffet rather than turbulence).



If you have never designed an airplane part before, let the real designers do the work!
User currently offlinePGNCS From United States of America, joined Apr 2007, 2821 posts, RR: 45
Reply 7, posted (1 year 10 months 2 weeks 2 days 22 hours ago) and read 5139 times:

Quoting barney captain (Reply 4):
So - you FLY the aircraft, yet don't understand the placard speed - is that correct?

I frankly find this beyond belief too.


User currently onlinehorstroad From Germany, joined Apr 2010, 260 posts, RR: 0
Reply 8, posted (1 year 10 months 2 weeks 2 days 22 hours ago) and read 5139 times:

Quoting barney captain (Reply 4):
So - you FLY the aircraft

did he say that? maybe he is a mechanic, FA, ramp agent or whatever


User currently offlinePGNCS From United States of America, joined Apr 2007, 2821 posts, RR: 45
Reply 9, posted (1 year 10 months 2 weeks 2 days 21 hours ago) and read 5135 times:

Quoting horstroad (Reply 8):
Quoting barney captain (Reply 4):
So - you FLY the aircraft

did he say that? maybe he is a mechanic, FA, ramp agent or whatever

Not here but elsewhere, plus it's in his profile.

Barney captain has good reason to ask this question as this is an EXTREMELY basic piece of information for a pilot of any sort to know.


User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 10, posted (1 year 10 months 2 weeks 2 days 16 hours ago) and read 5067 times:

Quoting Roseflyer (Reply 6):
Usually you have 4 speeds for landing gear.

And a max retraction speed.


User currently offlinetb727 From United States of America, joined Jun 2005, 1588 posts, RR: 9
Reply 11, posted (1 year 10 months 2 weeks 2 days 13 hours ago) and read 5020 times:

Quoting CosmicCruiser (Reply 10):
And a max retraction speed.

Which is the tricky one. It's significantly lower in the plane I fly, if you throw the gear for an emergency descent, you have to remember you are gonna have to slow it back up to put it up again if you so choose. Not a big deal really, just another step.



Too lazy to work, too scared to steal!
User currently offline9VSIO From United Kingdom, joined Dec 2006, 714 posts, RR: 2
Reply 12, posted (1 year 10 months 2 weeks 2 days 12 hours ago) and read 4994 times:
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Quoting horstroad (Reply 8):
did he say that? maybe he is a mechanic, FA, ramp agent or whatever

Well, he's been asking quite a lot of pilot related questions, and said in one of the other threads that he also instructs in the 737 sim for the type rating. His profile has already been mentioned on here. His questions are normally interesting though  



Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...
User currently offlineMax Q From United States of America, joined May 2001, 4458 posts, RR: 19
Reply 13, posted (1 year 10 months 2 weeks 2 days 10 hours ago) and read 4936 times:

It's not really an issue, at low altitude, below say 27000 feet your Mach No is going to be so much lower than the KIAS limit for gear extension it's not a factor, and at high altitude your KIAS will be so much lower than the mach limit it's not a factor.


Most, if not all modern Boeings use just one Mach / Speed limit for extension/ extended these days keeping it simple.


270 / .82 Is the limit on the 757 / 767 and I suspect it's pretty close to that on all subsequent Boeing models.



The best contribution to safety is a competent Pilot.
User currently offlinetb727 From United States of America, joined Jun 2005, 1588 posts, RR: 9
Reply 14, posted (1 year 10 months 2 weeks 1 day 21 hours ago) and read 4813 times:

Quoting Max Q (Reply 13):
270 / .82 Is the limit on the 757 / 767 and I suspect it's pretty close to that on all subsequent Boeing models.

Seems to be!

727 is 270/.83 to extend
200 to retract
VLE/MLE is 320/.83 and I am pretty sure you are gonna go deaf and/or chug through some fuel if you do that.

747 Classic
VLE/MLE 320/.82
VLO 270/.82
Gear retract can be 270/.82 or 250/.82 depending on plane.



Too lazy to work, too scared to steal!
User currently offlineCitationJet From United States of America, joined Mar 2003, 2434 posts, RR: 3
Reply 15, posted (1 year 10 months 2 weeks 1 day 17 hours ago) and read 4747 times:

Cessna actually specifies six landing gear design speeds for some Citations. However many of the speeds are the same for a given aircraft.
Vlo (extending) - Mach
Vlo (extending) - knots
Vlo (retracting) - Mach
Vlo (retracting) - knots
Vle (extended) - Mach
Vle (extended) - knots

Ref: FAA TCDS A1WI, for model Citation 525B, page 15.



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.
User currently offlineMax Q From United States of America, joined May 2001, 4458 posts, RR: 19
Reply 16, posted (1 year 10 months 2 weeks 1 day 10 hours ago) and read 4695 times:

Quoting tb727 (Reply 14):

VLE/MLE is 320/.83 and I am pretty sure you are gonna go deaf and/or chug through some fuel if you do that

Boy you have that right..



The best contribution to safety is a competent Pilot.
User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 17, posted (1 year 10 months 2 weeks 1 day 7 hours ago) and read 4667 times:

Quoting bueb0g (Reply 3):
Quoting HAWK21M (Reply 2):
That is the range.........Not to exceed BOTH.

You mean not to exceed either?

Thats correct.



Think of the brighter side!
User currently offlinezbbylw From Canada, joined Nov 2006, 1984 posts, RR: 6
Reply 18, posted (1 year 10 months 1 week 3 days ago) and read 4246 times:

Quoting barney captain (Reply 4):

So - you FLY the aircraft, yet don't understand the placard speed - is that correct?

  

Remember that during your ground school, the instructor is there for you. The airline or in the case of the UK sometimes, you are paying for that guy to teach you. I don't know what airplane you're on but it may be your first jet and some of the high speed/high altitude aerodynamics may be new. Make sure you get the airlines money out of your instructor!



Keep the shinny side up!
User currently offlinesmartt1982 From United Kingdom, joined Nov 2007, 225 posts, RR: 0
Reply 19, posted (1 year 9 months 4 weeks 1 day 4 hours ago) and read 3592 times:

Quoting zbbylw (Reply 18):
Quoting PGNCS (Reply 9):
Quoting barney captain (Reply 4):

I would just like to clarify something here if I could, this is a forum for finding out technical issues. As has been pointed earlier in this forum thread, yes I am a current 737 line pilot and a sim instructor. I have had very good experiences with the airliners forum in the past with clarifying issues in the past, up until this point!

I would like to add that I did expect that you have to obey both speed limit placards but I had heard from some students that they only had to obey one by another instructor. This puzzled me but I could not actually find in the Boeing manuals a definite AND clear answer. Too often in aviation you are told things both technical and operational and the person cannot point or refer to where this info has come from, hence the resson why I took the time to ASK the question on this forum.

Some of the replies posted here appear to be very negative and more casting an opinion on the person posng the question.

Think of me however you wish but I thought this forum was for finding out tech questions that could not be clearly answered else were

Thank you


User currently offlineFabo From Slovakia, joined Aug 2005, 1219 posts, RR: 1
Reply 20, posted (1 year 9 months 4 weeks 21 hours ago) and read 3509 times:

I suspect there is a "whichever is lower" or similar in the AFM, but cannot confirm right now.


The light at the end of tunnel turn out to be a lighted sing saying NO EXIT
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 21, posted (1 year 9 months 4 weeks 21 hours ago) and read 3498 times:

Quoting Fabo (Reply 20):
I suspect there is a "whichever is lower" or similar in the AFM, but cannot confirm right now.

Nope. The words out of the 737-800 AFM are:
"LANDING GEAR PLACARD SPEEDS - KNOTS IAS, INDICATED MACH
RETRACT V_LO(RET) = 235
EXTEND V_LO(EXT) = 270, M_LO(EXT) = 0.82

EXTENDED V_LE = 320, M_LE = 0.82"

There is no need for a "whichever is lower" because they're independent, not coupled, limits. If you're over M0.82 it doesn't matter what your IAS is, you can't extend the gear. If you're over 235 knots it doesn't matter what your Mach is, you can't extend the gear.

Because of the way the Mach and IAS lines work out, IAS is more limiting at low altitude and Mach is more limiting at high altitude but both limits are in force all the time.

Tom.


User currently offlineFabo From Slovakia, joined Aug 2005, 1219 posts, RR: 1
Reply 22, posted (1 year 9 months 4 weeks 21 hours ago) and read 3490 times:

Quoting tdscanuck (Reply 21):
Because of the way the Mach and IAS lines work out, IAS is more limiting at low altitude and Mach is more limiting at high altitude but both limits are in force all the time.

Which is in effect the same thing. But you are the one with the AFM, not me, so there is that.



The light at the end of tunnel turn out to be a lighted sing saying NO EXIT
User currently offlineSKC From United States of America, joined Oct 2012, 96 posts, RR: 0
Reply 23, posted (1 year 9 months 4 weeks 20 hours ago) and read 3475 times:

Quoting smartt1982 (Reply 19):
I would just like to clarify something here if I could, this is a forum for finding out technical issues. As has been pointed earlier in this forum thread, yes I am a current 737 line pilot and a sim instructor. I have had very good experiences with the airliners forum in the past with clarifying issues in the past, up until this point!

So, what did the other sim instructors or your chief pilot(s) say when you asked them this question? Did they all have different answers? Has to be listed in a company manual somewhere.

While this may be a technical forum, and the given info may be correct, I'd be careful about taking perfomance data from a group of anonymous internet people. There's no background check to register here.


User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 24, posted (1 year 9 months 4 weeks 19 hours ago) and read 3458 times:

Quoting tdscanuck (Reply 21):
Because of the way the Mach and IAS lines work out, IAS is more limiting at low altitude and Mach is more limiting at high altitude but both limits are in force all the time.

You beat me to it but yeah. just think though at high alt. mach is the only concern, you may not even be able to slow to the IAS speed.


25 smartt1982 : A very valid point indeed. Your very true in what you say and I do whenever I can speak to as many different people as possible but the great thing a
26 Jetlagged : I think it's more likely a case of the students not understanding what the other instructor has said correctly. You will either reach the 270 knot li
27 Mir : Actually, it's the other way around. You've got a VLO (in knots) and an MLO (in Mach). Both limits apply at all times. It's not one or the other. And
28 smartt1982 : Mir, are you referring to my previous questions?[Edited 2012-11-05 12:30:08]
29 Jetlagged : Logically it's still an OR (which means both limits apply, lowest one first). If it was 270 and 0.82 then you wouldn't reach the limit until both con
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