AF 447 Thread No. 5

[PJ2]

Takata;

Re your message #999:

Originally Posted by ACARS
.1/FLR/FR090601 0210 279334 06
EFCS1 X2,EFCS2X,,,,,,
FCPC2 (2CE2) /WRG:ADIRU1 BUS ADR1-2 TO FCPC2,HARD

About Svarin's concerns in relation to this "wiring fault".
It seems to be simply due to PNF selection of ADR3 in place of its own ADR1 displayed. Hence, he switched to ADR3 (wrong) shortly before ADR1 returned "good" again. A while later, it seems that ADR+IR 3 was switched for ADR+IR 2 on PF display.

Yes, possibly. But I wonder if the explanation is more straightforward? From the AMM:

(3) Fault detection and analysis (except for the internal FWS computer faults)

As soon as an internal or external fault is isolated, it is considered as being at DETECTED status.

The FWS computer which detected the fault must confirm it.

The fault duration affecting ARINC bus links is:

- 2 s for a label with its SSM coded FW or FT FLIGHT, for the SDACs
- 2 s + maximum of 500 ms or 5 cycles for a label not refreshed or if its parity is incorrect , for the SDACs and for the FWCs
- 2 s + 5 cycles for a label if its SSM is coded FW or FT FLIGHT, for the FWCs.

Then, the fault is at DECLARED status.

A declared fault must be sent to the CMC.

A DECLARED fault is then consolidated. This consolidation is performed by the computer which declared the fault. It consists in checking the duration of the fault or its recurrence.

If the fault is still present after 10 seconds or if it occurs 3 or more times during the flight, it is consolidated.

A fault which is declared not consolidated is transmitted to the CMC as being a TRANSIENT fault, with bit 19 of label 356 at
0 (INTERMITTENT).

A fault which is declared consolidated is transmitted to the CMC as being a PERMANENT fault with bit 19 of label 356 at
1
(HARD).

A declared fault, whether it is consolidated or not, is transmitted for correlation:
- a fault declared by a SDAC is transmitted to the FWCs,
- a fault declared by a FWC is transmitted to the opposite FWC,
- an ECAM control panel fault is transmitted to the FWCs.

The correlated message which is transmitted in any case to the CMC by the FWC 1 is stored in each FWC.

NOTE : Very few LRUs connected to the FWS, are not checked at the
BITE level but remain checked at the operational level.

(4) Correlation principle
In addition to one fault detection, each FWC starts a correlation process.

This correlation is only possible because every LRU which is acquired by the FWS is connected at least to two computers of the FWS.

This correlation is performed on the buses and on the analog data.

The correlation enables a greater precision on the origin of the fault.

- Example of a message not correlated:
If a fault is detected only by one FWS computer, the associated message will be:
FWCi(1WWi)/WRG:FMGECn BUS E GEN TO FWCi

- Example of a correlated message:
If the same fault is detected by two computers of the FWS, the associated message will be:
FMGECn(1CAn) BUS E GEN

The correlation process which is performed by the FWCs can be initiated only after the consolidation.

grity;

Yes, it means "Vertical Speed Selector", on the FCU - it also doubles as the FPA selector when the mode is in TRK-FPA.

An observation - (one of many, I suspect); Just so everyone is clear on this, the "MAX REC" on the MCDU is not displayed in red font as shown in the BEA Report. I suspect this is for emphasis only. The MAX REC is not a limitation but an advisory based upon both crew-entered TROP heights, and current weights and temperatures, (SAT). One doesn't attempt to climb above it but it wouldn't be a "limitation" in the same sense that the service ceiling of the aircraft is a certification limitation.

Thus far, in my reading of the Report, I cannot find clear comments on why the initial pitch-up occurred. The stick movement was brisk - 7deg (almost half-stick aft movement) in one second. As I posted earlier, I thought it might have been 4 to 5 degrees, which equated to about 3cm of aft stick movement or about roughly about six inches on a standard control column. This aft movement is far greater than that. We can understand a bit better why the aft stick movement during the cockpit confusion, but not the initial movement.

Still reading.