Airbus A350 XWB Flight test campaign

[A33Zab]

@Stuck_in_an_ATR:

FOT (Flight Operation Telex) 999.0076/09 refers.

BUSS activation comes with increased workload (manual flight, manual cabin press control, some FMS functions not available)
Once you select BUSS, it is for the remainder of flight because you won't be able to identify the faulty source anymore.

Agree the BUSS is not compensated for Mach (as it is not compensated for speedbrake) but that is not the reason for the FL250 threshold.

[HazelNuts39]

Originally Posted by A33Zab

Agree the BUSS is not compensated for Mach (as it is not compensated for speedbrake) but that is not the reason for the FL250 threshold.

Agreed that is not the reason stated by Airbus. However, if the BUSS had been intended to be usable above FL250 a lower value of the backup stall warning threshold would have been appropriate.

[A33Zab]

What is noticeable is the increase in the number of probes and ports and also
how they have been regrouped and placed at the very front end ...

A380 OAT sensors (for SAT on ground only) are located on the NLG.

That leaves the single AoA vane (other 3 are part of MFP) added in comparision with A380.

Don't know the exact reason, aerodynamical or accessibility for maintenance from inside the NLG wheel well?

Also the judiciary experts have noted that :

• Its utilization requests a lot of attention
• Its utilization is uneasy when changing the configuration
• Its activation is irreversible
• Its utilization requests regular training

• Increased workload.
• FCOM: S/F retraction, fly the top of the green area, for S/F extension, fly the bottom of the green area. Do not select CONFIG FULL.
• On ground it is fysical reversible, in flight I am not sure*), however it is procedural not reversible. See previous reply STUCK_ia_ATR.
• as should all extraordinary situations.

*) The BUSS image is generated in SDAC, if the ALT signal is absent for 500ms, SDAC will generate the BUSS image, if one reselects any ADR the ALT signal will be available again and SDAC will generate the normal speed display.

[A33Zab]

@HN39:

Think we are in the wrong thread.

Absolutely correct, but no comment on that one by airbus.

A330 SW CLEAN:

NORMAL 23° (fixed value)
ALTERNATE/DIRECT 10.8° -7.0° (max Mach compensated) = 3.8°
BUSS 8.6°

[AlphaZuluRomeo]

I was not talking about icing. Nor BUSS.

I was talking about the airspeed sensed being lower than the real airspeed with fixed pitot probes when the AoA is high, due to the (big) angle between aircraft axis and aircraft trajectory.
If the probe (such as MFP) aligns itself with the relative wind (AoA = 0) then the sensed airspeed is "right".

My point simply was that I feel it's not a bad idea to have that.

[HazelNuts39]

Originally Posted by AZR

If the probe (such as MFP) aligns itself with the relative wind (AoA = 0) then the sensed airspeed is "right".

Yes, provided the sensed static pressure is equal to the ambient pressure. I note that the static ports have moved more to the side of the fuselage and that perhaps reduces the 'position error correction' for high AoA's.

[CONF iture]

Will the 320NG be also equipped with the SSA and MFP ?
Are the SSAs playing a role in some protections ?

Regarding the BUSS :

Originally Posted by A33Zab

On ground it is fysical reversible, in flight I am not sure*), however it is procedural not reversible. See previous reply STUCK_ia_ATR.

I am also surprised it would not be reversible in flight as the only thing to do would be to initially stabilize the flight with a pitch and thrust and reengage one by one the ADRs and see how they make sense.

[Stuck_in_an_ATR]

@A33Zab. Haven't seen the FOT you mentioned. The explanation provided by Airbus seems a bit obscure, but still - thanks for info!

[A33Zab]

Will the 320NG be also equipped with the SSA and MFP ?
Are the SSAs playing a role in some protections ?

320NEO is advertised with new engine and sharklets. not with flight control system enhancements.
SSA is used for Y* Normal lateral law, don't know if its playing another role too.

@AZR:

The pitot of the MFP is fixed to its base and does not rotate 'into wind'.

@HN39:

The static ports (ISPs) are on an identical poistion as A330, only the Standby static ports are more on the side but is used for ISIS only.

[HazelNuts39]

A33Zab,
thanks for the info. As always. accurate and to the point.

[AlphaZuluRomeo]

Originally Posted by A33Zab

@AZR:

The pitot of the MFP is fixed to its base and does not rotate 'into wind'.

Oh, OK. My bad, then, and thanks for the information.

Well, it was a detail anyway (with extreme scenarii in mind)

[A33Zab]

Other interesting reading: FAST A350special

[FlightPathOBN]

It appears the A350 will do a flyover of the airshow on Friday...

[AlphaZuluRomeo]

Yep. It's in flight now (in the SE of France).

IIRC, Airbus said the fly-over will take place around 13h local.

[keesje]

It made the pass over the Paris Airshow last Friday.



Everything went smooth according to Airbus, but it will be a long time before we get the details

[DaveReidUK]

but it will be a long time before we get the details

It flew over the show at Le Bourget. What additional detail do we need?