Airbus (A320) engine out target speed/SRS after takeoff

[John Citizen]

I am a bit confused understanding the SRS (engine out) and V2.

For an engine failure after takeoff, the FCOM says
After lift-off, follow the Speed Reference System (SRS).

I always thought that if you follow the SRS as per FCOM, then this will give you V2 speed (if engine out). :confused:

In Australia, for our proficiency (CAO's) we are supposed to maintain :

Asymmetric flight tolerances (aeroplanes):
(b) indicated airspeed:
(i) initial climb — nominated 1 engine inoperative climb speeds
+ 5, - 0 knots;


This means maintain V2, +5, -0. I heard someone actually failed a proficiency test because they were outside these limits. :eek:

The takeoff performance preamble says Second Segment - V2 speed (constant KIAS).

Therefore you can conclude that you should fly at V2 (as close as you can) following an engine failure on takeoff.

Here are some quotes from the FCOM which confuse me :


In SRS mode, the aircraft maintains a speed target equal to V2 + 10 knots in normal engine configuration. When the FMGS detects an engine failure, the speed target becomes the highest of V2 or current speed, limited by V2 + 15 knots.


Therefore if you experience an engine failure airborne at V2 + 10, will the SRS now guide you to fly at V2 + 10 instead of V2 ?


Engine Out :

In the speed reference system (SRS) mode, the takeoff speed target is V2, or the current speed if it is higher but no more than V2 + 15. The magenta triangle indicates V2 in all cases.


Does this mean that the SRS does not always guide you fly V2 speed ?
Does this mean the SRS will guide you anywhere between V2 and V2 + 15 speed ?

How are we supposed to fly at V2 speed as required by the performance preamble and by the authority for our proficiency if the SRS will not guide us to do so ? :confused:

Do we now deliberately ignore the SRS (contrary to FCOM) and set an attitude on raw data to give us V2 speed ?:confused:

Or do we follow the SRS and fly at up to V2 +15 speed, contrary to performance preamble and proficiency requirements ? :confused:

Or do I just have no idea :eek:

[shortfuel]

Does this mean that the SRS does not always guide you fly V2 speed ?
Does this mean the SRS will guide you anywhere between V2 and V2 + 15 speed ?

yes
yes
the reason was quoted by yourself in your post

Your CAOs tell you to maintain your nominated OEI speeds....not V2. These can be anywhere btw v2 and v2+15. The a/c was designed and certified like this by your authorities. So failing someone on a 320 because he simply doesn't fly v2 in OEI...I think we/you are missing some details here.

Just fly this aircraft as it has been prescribed by the manufacturer.

[jb5000]

Plus - V2 is a minimum speed to guarantee obstacle margins.

A speed higher than V2 will give you a better second segment obstacle clearance, hence the 'increased V2' procedure for take off performance.

Flying higher than V2 when you already have reached the speed before the engine failure is not going to compromise take off performance, however accelerating at low level from V2 to V2+15 might!

[Paua]

Yes.
And Google DC10 accident Chicago

[PantLoad]

The standard quoted applies to antique aircraft....not the ultra modern Airbus. :D If you're flying a B-737, well....I'm sorry for you.
(Only joking!!!)

Fly the SRS speeds as directed by the Flight Directors. V2 is the minimum speed that gurantees the minimum required climb gradient.....IT IS NOT THE SPEED WHICH GIVES YOU THE BEST OEI CLIMB GRADIENT!!!! (Please refer to "Getting to Grips with Aircraft Performance" (by Airbus) to explain all this.)

If you're flying the SRS speeds as per the Flight Directors and the CAAV representative busts you, respectfully refer him/her to the above-mentioned publication (as well as the FCOM and the FCTM).

Fly safe,

PantLoad

[leftwing]

plus and V2 should indicate obsticles
I wont bother to repeat the quote but the second poster is correct, you have given the answer to your own question
:rolleyes: