UPDATE (Thu Jan 20): After the debacle on Tuesday, with the cancellation of 777 and 747-8 flights by multiple international airlines, it seems the FAA was embarrassed (or forced) into accelerating the issuance of AMOC approvals for additional altimeters, approving the 777 on Wednesday morning, and the number of altimeters approved and percentage of the US fleet covered has now grown very quickly:
Tuesday Jan 18: 2 altimeters and 45% of the US fleet
Wednesday Jan 19: 5 altimeters and 62% of the US fleet
Thursday Jan 20: 13 altimeters and 78% of the US fleet.

The result has been that most disruption has been avoided, although regional jets remain a concern, with some problems resulting from low visibility. However, the rapid pace of approvals, and the expectation from airlines that there won’t be “any material disruption going forward”, further discredits the FAA’s fearmongering over the weekend, not least because an AMOC has now been issued covering all 787 jets, which were supposedly the cause of greatest alarm. Suggestions that airlines would need to “swap out the altimeters” in a process lasting years and costing billions of dollars, also appear to be well wide of the mark. //

But the FAA’s statements appear to confirm that they are only issuing AMOCs approving altimeters to operate while the current 5G deployment restrictions remain in place: “The new safety buffer announced Tuesday around airports in the 5G deployment further expanded the number of airports available to planes with previously cleared altimeters to perform low-visibility landings.”

So it is perhaps no wonder Boeing is refusing to comment because they don’t want to get into a public shouting match with the FAA, despite the behind the scenes confrontation over the 777 at the beginning of this week outlined above. But you can be sure that many aviation interests are demanding that the restrictions continue permanently and the FAA is preparing for another showdown on July 5th, when the current six month period of restrictions is set to expire.