Could somebody please explain this - I kind of understand it - except why is it a lower speed ,the lighter the a/c is. I would have thought that it should be the other way around.Thanks Barry

It's the highest speed at which full control surface deflection is permitted. When the aircraft is lighter, the response of the aircraft to control surface motion is greater, so it is possible to overstress the aircraft. No snap rolls in a 737!Hope this helpsAllcott

Sometimes you can cause structural damage at speeds even lower than manuvering speed, they found out, in the Airbus Crash in New York. Moving the rudder from side to side rapidly, cause the Tail assembly to fall off, and they were below manuvering speed.

Hi Barry,Manouvering speed (called "Va" ) is the speed at below which the aircraft will stall rather than suffer damage to wing and/or control surfaces. In bumpy weather, where sudden forces may be applied to the aircraft, if you stay below this speed then your aircarft will stall (prefered) rather than suffer damage (not preferred). A stall you can recover from, physical damage is a little more difficult :)Bruce.

>Hi Barry,>>Manouvering speed (called "Va" ) is the speed at below which>the aircraft will stall rather than suffer damage to wing>and/or control surfaces. In bumpy weather, where sudden forces>may be applied to the aircraft, if you stay below this speed>then your aircarft will stall (prefered) rather than suffer>damage (not preferred). A stall you can recover from,>physical damage is a little more difficult :)>>Bruce.>As I stated in my post above, this has proven to be an incorrect assumption , and has been discussed in several articles in Flying Magazine, in reference to the JFK Airbus Crash. Even below manuvering speed, an aircraft can sustain structural damage, if the controls are moved rapidly back and and forth.

Manouvering speed refers to elevator deflection, not rudder. Hence the confusion.

Yes, I stand corrected. Thanks Bob :)Bruce.

>Manouvering speed refers to elevator deflection, not rudder.>Hence the confusion.No confusion, and manuvering speed is a "speed" and has nothing to do with what control might cause an overstress on the airframe. You could be headed straight down in a dive, with the elevator at neutral, exceeding manuvering speed by a considerable amount, and rip the wings off the aircraft with a very small elevator deflection from neutral.

>Could somebody please explain this - I kind of understand it>- except why is it a lower speed ,the lighter the a/c is. I>would have thought that it should be the other way around.>Look it up in Rod Machado's Private Pilot Handbook. He makes it simple by explaining through pictures.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2http://www.precisionmanuals.com/images/forum/747400.jpg

"except why is it a lower speed ,the lighter the a/c is. I would have thought that it should be the other way around."The basic reason is that as weight increases lift must increase and for any given airspeed you need to fly the airfoil at a higher angle of attack and therefore closer to the critical angle or attack (where the airfoil stalls). So you are closer to the stall and in theory would stall earlier if a sudden increase in load factor were experienced at a heavy weight as opposed to a lighter weight. As it was already mentioned when flying at Va you would likely stall the aircraft before causing structural damage. At higher weights you can be going faster and still be closer to a stall than a lighter slower moving aircraft.That is a simplistic description, but it all ties into AoA. Also Va is not perfect. All kinds of bad things can still happen at Va. Either AOPA or Flying had a good bit on Va in recent months.

You can find a thorough, well-illustrated explanation of maneuvering speed beginning on page 3-30 in Chapter 3, "Aerodynamics of Flight" in the Pilot's Handbook of Aeronautical Knowledge, one of many useful Training Handbooks and references available for free download (in PDF format) from the FAA's Web site at:http://afs600.faa.gov/srchFolder.asp?Categ...raininghandbookThe Airplane Flying Handbook, another reference located at the same site, offers the following concise, practical definition of maneuvering speed (abbreviated Va) on p. 4-10:"The design maneuvering speed is the maximum speed at which the airplane can be stalled or full available aerodynamic control will not exceed theairplane

>You can find a thorough, well-illustrated explanation of>maneuvering speed beginning on page 3-30 in Chapter 3,>"Aerodynamics of Flight" in the Pilot's Handbook of>Aeronautical Knowledge, one of many useful Training Handbooks>and references available for free download (in PDF format)>from the FAA's Web site at:>>http://afs600.faa.gov/srchFolder.asp?Categ...raininghandbook>>The Airplane Flying Handbook, another reference located at the>same site, offers the following concise, practical definition>of maneuvering speed (abbreviated Va) on p. 4-10:>>"The design maneuvering speed is the maximum speed at which>the airplane can be stalled or full available aerodynamic>control will not exceed the>airplane

Read the information on the Airbus crash that's available on the NTSB Web site (esp. http://www.ntsb.gov/Recs/letters/2002/A02_01_02.pdf), and you'll find that the basic definition of Va still applies.The NTSB found that several factors (pertaining to transport-category aircraft) contributed to the ultimate failure, and they aren't necessarily relevant to the general discussion in this thread. (For more information on this accident, see http://www.ntsb.gov/events/2001/AA587/default.htm).Also note that the definition quoted above says that:"At or below this speed, the airplane will usually stall before the limit load factor can be exceeded..."N.B. "usally"For more information about the U.S. certification standards for aircraft, see Parts 23 and 25 of the FARs(http://www.risingup.com/fars/info/23-index.shtml and http://www.risingup.com/fars/info/25-index.shtml)

Those who are interested in learning more about this topic can read J. Mac McClellan's column from the February 2005 issue of Flying magazine, which is available online at:http://www.flyingmag.com/article.asp?secti...mber=1&preview=Note that the column ends thus:"Despite our misunderstanding of the degree of airframe structural protection offered by Va, pilot induced structural failures, when flying at or below that speed, are very rare. The typical scenario of airframe failure in general aviation involves the loss of control, which quickly leads to a spiral dive with airspeed increasing very rapidly. When the pilot recognizes the dive

isnt it the minimum speed for a given weight with gear up and zero flaps?Johan[A HREF=http://jdserver.no-ip.com]Personal Server[/A]or..http://62.238.33.10A LITTLE LESS CONVERSATION, AND A LITTLE MORE ACTION PLEASE!