What are V-speeds?
Joined: Apr 2004
Posts: 83
Likes: 0
From: Haywards Heath
V for Velocity.
100%.
No argument.
VS is indeed a vertical speed mode in Flight Guidance Systems / autopilots. Nothing to do with V1/Vr/V2/Vmca etc.
I also agree that Vat is used to define aircraft Category (A,B or C etc.) for approach purposes. Vref changes with weight on the day but Vat, for PANS OPS purposes, remains a fixed max weight speed.
100%.
No argument.
VS is indeed a vertical speed mode in Flight Guidance Systems / autopilots. Nothing to do with V1/Vr/V2/Vmca etc.
I also agree that Vat is used to define aircraft Category (A,B or C etc.) for approach purposes. Vref changes with weight on the day but Vat, for PANS OPS purposes, remains a fixed max weight speed.
Fleet Manager
Joined: Apr 2001
Aviation Qualifications: ATPL
Posts: 7,448
Likes: 310
From: various places .....
Vo -- operating manoeuvring speed. Similar to Va.
Current references to look at include
(a) FAR Final Rule Making - Small Airplane Airworthiness Review Program Amendment No. 4 (and search for Vo),
(b) FAR 23.1507 (which is where it is defined), and
(c) FAR 23.1583 (where it is required to be published if determined).
Just how relevant these references are to your particular POH I'm not sure .. but they give you a starting point to research the matter.
.. I gotta get a life ...
Current references to look at include
(a) FAR Final Rule Making - Small Airplane Airworthiness Review Program Amendment No. 4 (and search for Vo),
(b) FAR 23.1507 (which is where it is defined), and
(c) FAR 23.1583 (where it is required to be published if determined).
Just how relevant these references are to your particular POH I'm not sure .. but they give you a starting point to research the matter.
.. I gotta get a life ...
Joined: Oct 2002
Posts: 61
Likes: 0
From: Sum Ware
Okay let's see:
V1: The decision speed in the event of an engine failure during the takeoff roll at which it is possible to continue the takeoff and achieve the screen height within the normal takeoff distance available or to bring the aircraft to a full stop within the emergency distance available.
Thus, the takeoff must be abadoned with an engine failure below V1 and the takeoff must be continued with an engine failure above V1.
If the Takeoff Weight is limited by the Takeoff Distance Available (TODA), Takeoff Run Available (TORA), or Emergency Distance Available (EMDA), the V1 speed relates to a single point along the runway where the pilot will have the decision to continue or abort the takeoff in the event of an engine failure. V1 Cannot be less than VMCG; V1 cannot be greater than Vr or VMBE.
Vr: rotation speed where the speed at which the pilot initiates rotation during the takeoff to acheive V2 at the screen height even with an engine failuare. Vr cannot be less than 1.05 VMCA divide by 1.1 or 1.05 VMU.
V2: takeoff safety speed achieved by the screen height in the event of an engine failure that maintains adequate directional control and climb performance properties of the aircraft. To be more specific, V2 cannot be less than Vs x 1.20 and VMCA x 1.10.
V3: where the all-engine-operating takeoff climb speed the aircraft will achieve at the screen height.
V4: speed is the all-engine-operating takeoff climb speed the aircraft will achieve by 400' and is used as the lowest height where accleration to flap retraction speed is initiated.
VMU: minimum demonstrated unstick speed at which it is possible to get airborne on all engines and to climb out without hazard.
VMBE: maximum brake energy speed on the ground which a stop can be accomplished within the energy capabalities of the brakes.
I hope this will help!
V1: The decision speed in the event of an engine failure during the takeoff roll at which it is possible to continue the takeoff and achieve the screen height within the normal takeoff distance available or to bring the aircraft to a full stop within the emergency distance available.
Thus, the takeoff must be abadoned with an engine failure below V1 and the takeoff must be continued with an engine failure above V1.
If the Takeoff Weight is limited by the Takeoff Distance Available (TODA), Takeoff Run Available (TORA), or Emergency Distance Available (EMDA), the V1 speed relates to a single point along the runway where the pilot will have the decision to continue or abort the takeoff in the event of an engine failure. V1 Cannot be less than VMCG; V1 cannot be greater than Vr or VMBE.
Vr: rotation speed where the speed at which the pilot initiates rotation during the takeoff to acheive V2 at the screen height even with an engine failuare. Vr cannot be less than 1.05 VMCA divide by 1.1 or 1.05 VMU.
V2: takeoff safety speed achieved by the screen height in the event of an engine failure that maintains adequate directional control and climb performance properties of the aircraft. To be more specific, V2 cannot be less than Vs x 1.20 and VMCA x 1.10.
V3: where the all-engine-operating takeoff climb speed the aircraft will achieve at the screen height.
V4: speed is the all-engine-operating takeoff climb speed the aircraft will achieve by 400' and is used as the lowest height where accleration to flap retraction speed is initiated.
VMU: minimum demonstrated unstick speed at which it is possible to get airborne on all engines and to climb out without hazard.
VMBE: maximum brake energy speed on the ground which a stop can be accomplished within the energy capabalities of the brakes.
I hope this will help!
