A320 pro-abn eng 1(2) aircraft fadec supply
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One of the FADEC functions is the thrust reverser control.
On the other hand ,the aircraft supplies the FADEC during 5 minutes after the acft. is energized, and when the IGN/START is selected and below 12%N2. Above 12%N2 the FADEC is self powered. The acft. will supply the FADEC again when the MASTER SWITCH is off and below 12%N2, for 5 minutes.
I may be wrong, but youīre not going to use the reverser, anyway.
On the other hand ,the aircraft supplies the FADEC during 5 minutes after the acft. is energized, and when the IGN/START is selected and below 12%N2. Above 12%N2 the FADEC is self powered. The acft. will supply the FADEC again when the MASTER SWITCH is off and below 12%N2, for 5 minutes.
I may be wrong, but youīre not going to use the reverser, anyway.
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We may get this fault in flight also during which FADEC is powered by its own alternator and will be self powered until N2 drops below 10% (IAE) or 12% (CFM). My question is why is Reverser inop in this case as it never lets N2 to drop below 10 or 12% ?
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Throttle control lever sends reverse thrust command independantly to EIU, ECU. EIU closes inhibition relay switch and then only ECU deploy command goes through to hydraulic control unit which activates actuators through respective hydraulic system. In case of IAE, ECU is called EEC. Apparently it needs 28V DC. That is why REV inop.
Last edited by vilas; 7th Aug 2013 at 14:27.
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The diagram shows EEC/ FADEC getting aircraft 28V DC supply. Failure of this A/C 28V supply to both EEC channels may be unable to process deploy command causing REV inop.
Last edited by vilas; 9th Aug 2013 at 07:48.
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Gentlefolk,
One way to provide high integrity thrust reverse systems is to ensure that no one computer has all controls in its power.
Role [1] of the EIU is to take aircraft power and switch 28Vdc to the FADEC as required - as Flappo post #2.
Role [2] of the EIU is to take aircraft power and switch 28Vdc to the TR Isolation Valve solenoid, when required for Thrust Reverse operation.
Role [3] of the FADEC is to close the TR Isolation Valve solenoid circuit, when required for Thrust Reverse operation. N.B. the FADEC must not* power this circuit from either the 28Vdc EIU supply or from its dedicated generator systems.
Role [4] of the FADEC is to electrically power and actuate other TR valves, when required for Thrust Reverse operation.
* This particular electrical power isolation may have a permissible failure rate; the details are another story.
The combination of the above roles ensure that a TR system could only deploy with concurrent EIU and FADEC command.
I therefore speculate that the reason for the ECAM warning correlation between FADEC and TR operation, is due to electrical supply fault detection/reporting for these 28Vdc buses having shared hardware insdie the EIU.
0'n'1
One way to provide high integrity thrust reverse systems is to ensure that no one computer has all controls in its power.
Role [1] of the EIU is to take aircraft power and switch 28Vdc to the FADEC as required - as Flappo post #2.
Role [2] of the EIU is to take aircraft power and switch 28Vdc to the TR Isolation Valve solenoid, when required for Thrust Reverse operation.
Role [3] of the FADEC is to close the TR Isolation Valve solenoid circuit, when required for Thrust Reverse operation. N.B. the FADEC must not* power this circuit from either the 28Vdc EIU supply or from its dedicated generator systems.
Role [4] of the FADEC is to electrically power and actuate other TR valves, when required for Thrust Reverse operation.
* This particular electrical power isolation may have a permissible failure rate; the details are another story.
The combination of the above roles ensure that a TR system could only deploy with concurrent EIU and FADEC command.
I therefore speculate that the reason for the ECAM warning correlation between FADEC and TR operation, is due to electrical supply fault detection/reporting for these 28Vdc buses having shared hardware insdie the EIU.
0'n'1
