A320 S speed question
Joined: May 2004
Posts: 308
Likes: 3
From: Down under land
wheresthecoffee...I know we are all really saying the same basic stuff here but the definitions of manoeuvre speed and target speed are not the same as you say. The target is, just like aiming my gun, is where I'd like my bullet to go. As gnads says - the bus, in managed, needs something to aim for and provides a margin well above the minimum to as to provide for things like challenging atmospheric conditions etc. So knowing this and dependent on the conditions at the time (as we are all talking about here) we can use our knowledge to provide for a more efficient operation.
Airbus doesn't pay for your fuel.
Airbus doesn't pay for your fuel.
Joined: Jan 2001
Posts: 1,693
Likes: 161
From: home
Straight from the FCTM:
"If selected speed is to be used to comply with ATC, the requested speed should
be selected on FCU. A speed below the manoeuvring speed of the present
configuration may be selected provided it is above VLS."
"If selected speed is to be used to comply with ATC, the requested speed should
be selected on FCU. A speed below the manoeuvring speed of the present
configuration may be selected provided it is above VLS."
Joined: Jun 2002
Aviation Qualifications: ATPL
Posts: 2,238
Likes: 218
From: Eden Valley
Originally Posted by Right Way Up
Straight from the FCTM:
"If selected speed is to be used to comply with ATC, the requested speed should
be selected on FCU. A speed below the manoeuvring speed of the present
configuration may be selected provided it is above VLS."
"If selected speed is to be used to comply with ATC, the requested speed should
be selected on FCU. A speed below the manoeuvring speed of the present
configuration may be selected provided it is above VLS."
FCTM & the Instructor Support Manual states similar.
The FCTM is highly recommended reading- for old Boeing boffins especially!
Joined: Jun 2005
Posts: 174
Likes: 0
From: Citizen of the World
No problem in flying below S speed by a few knots if required by ATC speed constraint. All in FCTM and FCOM. Poor understanding of systems by pilots coming from other manufacturers' types, not helped by poor (systems)training by both Airbus and airlines/TRTOs. As stated earlier, S speed is a target speed used by autoflight system with A/THR engaged using managed speed. Use selected speed and you can fly any speed right down to VLS. Of course, as you approach VLS, your protection above the stall reduces. Using flap and/or gear unnecessarily simply means you're burning fuel for no good reason. You can fly below S speed with Flap 1 (slats only) if you want to, but always best to respect your company's SOPs. If you're not happy with them, talk to your Chief Pilot! You can always ask ATC if 180/185 is OK and the required tolerance is +/- 10 kts.
