AW: Clarification Requested on two items associated with Airbus 

Petition for Exemption 

[Note: This e-mail included two Airbus-proprietary PDF attachments, neither of which is 

posted to the Federal Register due to the confidential nature of the material: 

• June, 2008 board-meeting document, ref. no. V03MN081446 

• Distributed Primary Flight Controls Architecture P4.14d] 

from: 

Koenig, Michael 

to: 

Stephen Happenny 

10/15/2010 08:44 AM 

Hello Steve, 

This is to provide the Airbus answer to the two points you requested clarification for. 

(1) Does the A350-900 airplane design include a pair of spoilers that will have an 

electrical back-up actuation? Please provide a reference number for documentation. 

(2) Is it correct that in case of total loss of all hydraulic power in combination with a 

significant damage of the pressurized fuselage, the aircraft will still be able to deploy a 

pair of spoilers in order to descend quickly to a safe altitude? 

Answer: 

The A350-900 is fitted with a pair of spoiler EBHA (Electrical Back-up Hydraulic 

Actuator) which in case of a hydraulic system failure can work as an electrical actuator. 

This is documented in the ATA27 Certification Plan (Ref. 00V270P0000/P00). 

Note: For the A350, in case of loss of one engine, all the Primary Flight Control 

Actuators remain available. In this case, both hydraulic circuits are fed by the two pumps 

on the remaining engine. This is also documented in ref. 00V270P0000/P00. For 

illustration please find a [Airbus proprietary] schematic of the A350-900 flight controls 

architecture attached. 

In the context of the FAR 25.841 amdt 87, we follow the certification policy set forth in 

the FAA Interim Policy on High Altitude Cabin Decompression, ref. ANM-03-112-16: 

Quote 

In analyzing system and structural damage caused by fragments from an UEF, additional 

structural damage can be assumed to be limited to that engine. Regarding engine powered 

systems, other than loosing the thrust, engine bleed air, and engine accessory power on 
the engine suffering the UEF, the operation of other airplane systems can be assumed to 

be normal. Therefore, the airplane should be capable of performing a Vmo/Mmo

emergency decent (i.e., spoilers fully deployed if appropriate, maximum descent rate, 

Vmo/Mmo speed). 

Unquote 

The agreement reached between EASA and Airbus cited below: 

Quote 

• Hydraulic System power is lost from the failed engine, but there is no additional 

damage to the hydraulic lines from the UERF. 

• One Green and One Yellow Pump on remaining engine available. Thus all 

spoilers remain powered and are capable of meeting the emergency descent 

criteria, analysis will be contained in Exemption Dossier. 

Unquote 

This is documented in the minutes of 2nd TBM which took place 10-11 June 2008, ref. 

V03MN0814469 (attached) [the referenced document is Airbus proprietary and is 

therefore not posted in the Federal Docket]. 

Could you please let me know if this clarifies the issue. 

Regards from Indian Summer in Hamburg 

Michael König 

Michael König 

Product Integrity - EAAC2 

Certification Manager ATA 21, 38 

Airbus Operations GmbH 

Kreetslag 10 

D-21129 Hamburg (Germany) 

Phone: +49 40 743 80285 

Fax: +49 40 743 76489