Emer Elec and Gear Down

[ikan_terbang]

Hi everyone.
I was looking thro HVN FCTM AO-024 P2/4 dated 24 June 2009 (Air Vietnam) Abnormal operations for Emergency Electric Configuration.Somewhere in the middle it states "Landing Gear will be delayed until reaching 1000 ft"
and available flight time is limited to 22 minutes on battery. Applicable MSN 0590-0650

I am doing a conversion training now and looking thro my manual (Not Air Vietnam) there is no mention of any heights for gear extension nor remaining battery time for the same procedure.The FCTM is also dated 24 June 2009 Applicable : ALL

I am just wondering why the discrepancy. And which procedure is more acceptable ( both might be right of course!!)

Any plausible explanation please
thank you

[Dan Winterland]

MSN 590 to 650 are old aircraft and probably have the old RAT which is affected by the lowering of the gear as it sits in airflow disturbed by the noseleg. For this reason, the aircraft goes onto batteries only which last 22 minutes. If you go around and can get the gear up, there is a procedure for re-instating the emergency generator, powered by the Blue system through the RAT. Later aircraft (for which it seems the more recent manual in your possession has been written) have an improved RAT fitted which will continue to work once the gear is lowered.

Although the later document says "All" it will refer to all the aircraft in the fleet of the operator for which that manual has been written. For example, if it was an easyJet manual, it will say ''All'', as all their airframes were dleived after the new RATs were fitted as standard. This highlights the dangers of using manuals not written for your aircraft. It's important with any aircraft to check the manual is applicable for the airframe your are flying. Even among fleets in the same airline there can be large differences.

[ikan_terbang]

Thanks for the explanation as well as the danger of using manuals not intended for the AC fleet I am flying.

[DCDriver]

Additionally, the reasons for delaying lowering the gear until 1000' are:

Capts ND is lost (older-style RATs, most likely on the msn's quoted above)

and

The a/c goes into Direct Law with selection of gear down, so auto pitch-trim is lost - you will see "use manual pitch trim" in amber on the PFD. Hence, Airbus consider it better to be in trim for landing (Conf 3) prior to lowering the gear.

DCD

[duyentranvan]

hey ikan terbang, how come you no plepare for this study? I will loster to fly with you and then teaching you some airbus plocedure

[ikan_terbang]

Hi DCD thanks for the comment.....just checked my manual (Newer RAT installed) On FCOM 3.02.24 pg20, the ND 1 is lost in flight when the electric network switches over to BAT at appox 100 kts.

So I guess for both the Older RAT and Newer RAT, they have the same property of shedding the ND 1 when the BAT connects to the Elec Network

As for GEAR down at 1000ft , even tho my manual is silent on this, It makes good sense to delay it as per your reasoning.

Regards