Mark Twyman. Customer Support Regional Manager FMC Eaton. All rights reserved..

Transcription

1 787 EPAS Actuator Components, Function and Maintenance Mark Twyman Customer Support Regional Manager FMC

2 Agenda EPAS Actuator Description EPAS Actuator Main components EPAS Actuator Normal operation EPAS Actuator Emergency operation EPAS Bottle Sub-Assembly Description EPAS Bottle Sub-Assembly Operation EPAS Squib - Life limit Eaton repair process & capabilities EPAS Issue System un-commanded activation 3

3 EPAS Actuator - Description Emergency Power Assist System (EPAS) Actuator Assembly is installed in all 8 Passenger Entry Doors (PED) of the Boeing 787-8, -9, -10 aircraft. Eaton Part Number Boeing Part Number S421Z802 EPAS Directly integrated into the hinge of the PED Controls/Dampens the speed in normal operation Provides rapid assist power opening the door in an emergency EPAS Actuator Assembly is an integrated actuator Hydraulic system, Actuator and replaceable gas bottle assembly Pressure is monitored on a dynamic basis by the EICAS system 4

4 EPAS Actuator Main components Gas bottle assembly ( ) Pressure reducer & relief valve assembly ( ) Flow regulator (57355) Actuator Rod ( ) Pneumatic piston ( ) Hydraulc Manifold assembly ( ) Fluid reservoir 5

5 EPAS Actuator Main components Gas bottle assembly Reservoir filled with high pressure 90% nitrogen gas, 10% helium to aide in leak detection Flow regulator valve assembly Controls fluid flow to the actuator system, dampening door during open / close operation Pressure reducer & relief valve assembly Pressure reducer senses downstream pressure and achieves a force balance against spring load, the relief valve function provides protection against over-pressurization (Normal & Emergency operation) Fluid reservoir Spring loaded piston reservoir ensures there is sufficient fluid in the hydraulic snubber Bleed port assembly Bleeds air from hydraulic fluid reservoir 6

6 EPAS Actuator Normal operation EPAS Actuator Assembly provides full-stroke damping of the passenger door to prevent injury to personnel and / or aircraft damage due to wind, residual pressure into the cabin, or accidental emergency actuation Damping function is provided by pushing hydraulic fluid through the flow regulator assembly to control the speed of the piston rod Rod pushes hydraulic fluid from one side of the damping chamber in the Manifold Assembly, through the flow regulator into the other side of the damping chamber Flow regulator provides control the actuator / PED speed in both directions (extend - door open, retract - door close) 7

7 EPAS Actuator Emergency operation Emergency operation of the EPAS actuator assembly is initiated at the PED With PED armed and the door handle rotated, an electrical signal commands the squib activation which release high pressure gas to the actuator Emergency opening of a PED at normal and adverse attitudes takes less than 4 seconds Allows deployment of the escape slide during the PED opening motion High-pressure gas travels through the pressure reducer, where the actuator pressure is regulated to provide a constant force for the PED motion This safely opens the door in the emergency mode 8

8 EPAS Actuator Installation Drawing 9

9 EPAS Bottle Sub-Assembly Description The EPAS Gas Bottle Assembly (Alternate PN ) is a Line Replaceable Unit (LRU) and is consists of the following major components: Gas bottle Pressure/Temperature Transducer Squib The Squib is a Life Limited component that must be replaced every 10 years Pressure Transducer Gas Bottle Squib Squib replacement procedure is in accordance with the Eaton CMM 10

10 EPAS Bottle Sub-Assembly Detail Description Gas bottle - The CRES stainless steel bottle Designed IAW DOT 39 requirements (non-refillable bottle) Has a design life of 20 years. No requirement to remove the bottle for periodic hydrostatic testing / certification Reduces repetitive maintenance / costs Filled to degrees F Pressure/temperature transducer - The built-in pressure transducer provides continuous monitoring of the internal bottle pressure and incorporates a temperature compensation design Squib Electro-Explosive Device (EED) When activated, the squib actuates a piston to puncture the rupture disc releasing gas to the door actuator system 11

11 EPAS Bottle - Operation Intact vs Punctured Bottle Squib 12

12 EPAS Bottle - Squib life limit Life Limited by design requirements to (10) years The Squib (EED) is an LRU and can be replaced in the field without removal of the Bottle Assembly or Actuator Assembly there is no need to send units back to Eaton for squib replacement Reference CMM Eaton will begin stocking spare Squibs by Q months before the first aircraft deliveries will reach 10 years in service 13

13 Eaton repair process & capabilities Eaton Los Angeles is an FAA/EASA/CAAC Certified Repair and Overhaul Facility Repair instructions for the EPAS Gas Bottle Assembly are limited to procedures to inspect / test the pressure transducer, replace the Squib or the Nameplate as required Reference CMM Warranty Process - Return bottles to Eaton for investigation if bottle has pressure but is out of spec Bottle should be shipped HAZMAT, see CMM TASK F-816-A01 for packing information If bottle is found dis-charged or has evidence of tampering, warranty will be denied and the bottle will be scrapped If bottle is found to be low pressure, warranty coverage may be considered If the bottle is found to meet all specs, Eaton will recertify bottle and ship back to customer with 8130 tag 14

14 Eaton repair process & capabilities Eaton is currently working on a new revision of CMM Current CMM only determines if there is adequate pressure in Bottle Cannot confirm if Bottle has been discharged Revision to include the following updates Instructions to replace Life Limited Squib Updated Gas Bottle Integrity Check will differentiate between low pressure bottle and discharged bottle Instructions on scrapping discharged bottles Define re-certification process for bottles CMM schedule release TBD Goal: Limit un-necessary return of EPAS bottles 15

15 EPAS Issue System un-commanded activation Issue: Increase of in-service EICAS status messages related to EPAS Module, and/or EPAS Bottle with or without inadvertent squib fire command issued during ground operations References: Described in Boeing FTD Model Affected: 787-8, Status: Root cause has been identified and found to be and associated piece of equipment supplied by another manufacturer. It is our understanding that Boeing and that other supplier have a plan in place to remedy the condition 16

16 Questions/Comments 17

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