感谢同事发现的问题。
A350 FCOM 中有两处对 RAT 自动放出有说明：
- FCOM DSC-24-10-20 A APU GENERATOR
- FCOM DSC-24-10-40 A RAM AIR TURBINE (RAT)
2024 年 10 月之前的版本中，两处的逻辑是一致的：所有 AC BUS 丢失后 RAT 会自动放出。但之后的版本中，DSC-24-10-40 A RAM AIR TURBINE (RAT) 处的描述就变成了：
If both AC 1A and AC 2A or both AC 1B and AC 2B busbars are lost in flight, the RAT extends automatically
而 DSC-24-10-20 A APU GENERATOR 依然是所有 AC BUS 丢失后才会放出：
In flight, if the entire normal AC network (AC 1A, AC 1B, AC 2B, and AC 2A busbars) is lost, the RAT will be deployed
空客回复说 APU GENERATOR 部分确实没有更新，后续会更新。
不过奇怪的是，这么大的修改一般来说会有相关文件进行说明，比如 MOD, ISI, TFU 等等，但在 airbusworld 上完全找不到。空客回复也说并没有相关文件，只提到 AMM 上就是这个逻辑。但由于 A350 的 AMM 是线上版，也看不出 AMM 是什么时候修改的。
TR-81739841 原文
Q1
There are two references to automatic RAT extension in the manual:
- FCOM DSC-24-10-20 A APU GENERATOR
- FCOM DSC-24-10-40 A RAM AIR TURBINE (RAT)
In versions prior to October 2024, the logic was consistent in both sections: the RAT automatically extends if all AC buses are lost.
However, in later versions, the description in DSC-24-10-40 A RAM AIR TURBINE (RAT) was changed to:
If both AC 1A and AC 2A or both AC 1B and AC 2B busbars are lost in flight, the RAT extends automatically
while the text in DSC-24-10-20 A APU GENERATOR still states:
In flight, if the entire normal AC network (AC 1A, AC 1B, AC 2B, and AC 2A busbars) is lost, the RAT will be deployed
The two descriptions are not consistent. Could you please clarify the reason for this discrepancy?
A1
In Oct 24, the RAT extension logic condition described in FCOM DSC-24-10-40-10-00013541.0003001 has been updated to reflect the logic applicable on the aircraft.
- Before Oct 24: “If the AC 1A, AC 1B, AC 2B, and AC 2A busbars are lost in flight, the RAT extends automatically.”
- After oct 24: “If both AC 1A and AC 2A or both AC 1B and AC 2B busbars are lost in flight, the RAT extends automatically”.
On the other hand, the FCOM DSC-24-10-20-10-00001786.0001001 APU GENERATOR has not been updated (dated Dec 2015).
We agree this may generate confusion and needs to be clarified.
We take this point into consideration for future FCOM modification.
We thank you for your input. We remain available should you require any additional information or assistance.
Q2
Do you have any other relevant materials (such as ISI, TFU, etc.) that detail the modifications to this RAT logic?
A2
We confirm there is no RAT modification logic associated with the update of FCOM DSC-24-10-40-10-00013541.0003001.
As stated in the previous answer, this is to reflect the logic applicable on the aircraft.
This logic is described in CSC AMM A350-A-24-24-XX-01001-04CA-A AC Emergency Generation:
Ҥ5 (2) For the automatic mode, two logics control the extension of the RAT module:
- 230VAC main busbars 1A and 2A not available
- 230VAC main busbars 1B and 2B not available.”
