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Old 18th July 2019 | 17:31
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FlightDetent

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From: Commuting not home
Thanks @oggers.

My A/C does not have the compensation feature but does have DA/H entry into the FMS. Having never seen what the boxes with the compensation are actually capable of, I let my mind loose too much.

Here's how I could explain now:

1) from the other instances of "temperature compensation" in the regulation, it is clear that the term does not exclusively reference an FMS feature.

2) in the case of AMC2 SPO.OP.116 (B) if we believed it applied solely to operations with the FMS compensation function, then (above the procedures' cold limit)
- (i) pilots with such feature are instructed not to correct the angle (FAF) nor decision minima (DA/H)
while pilots without such equipment, at the absence of EASA guidance but still pursuant to PANS-OPS, would need to
- (ii) not correct the angle (protected) but at the same time increase the minima by making a manual correction.

Clearly, 2 (i) and (ii) above would result in opposing guidance for the same approach under identical outside conditions. Hence the argument stands that the premise of 2) is false, and so AMC2 SPO.OP.116 (B) should be interpreted as being applicable to any form of temperature compensation, in a broader sense.

Additionally, increasing DA/H by a manual temperature correction and keeping the profile itself unchanged would bring the geometrical point of decision further from the runway, invalidating the RVR limit calculation. Avoiding this, as discussed in one of the threads of late, might be the actual reason behind the instruction of AMC2 SPO.OP.116 (B) not to compensate - to be applied to all approaches above the lowest promulgated temperature.

Hope it checks.
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