Originally Posted by
Smythe
Sorry, but that was directly from the FAA response to Boeing on the wings, the wind loads and lack of indicators that the wings are locked.
note 'must add' means it wasnt there?
More than one means must be available to alert the flightcrew that the wingtips are not properly positioned and secured prior to takeoff. Each of these means must be unique in their wingtip-monitoring function. When meeting this condition, the applicant must add a function to the takeoff warning system, as required by § 25.703(a)(1) and (2), to warn of an unlocked or improperly positioned wingtip, including indication to the flightcrew when a wingtip is in the folded position during taxi.
No, "must add" doesn't mean it wasn't there, it means that the FAA and Boeing didn't agree on the level of redundancy. Boeing is putting all the indications in EICAS, the FAA wants more. This is nothing new - it's a basic disagreement about EICAS that dates to the 747-400 (and in some cases to the 767/757).
The FARs say 'more than one'. Pre-EICAS this meant more than one light bulb driven my more than one monitor - because one can fail. Starting with the 747-400, EICAS is fault tolerant and multiple redundant, using inputs from multiple systems, running Level A flight critical software. Boeing thinks this complies with the multiple indication requirement, some at the FAA disagree. On previous programs (747-400,777, 767-400, 787, 747-8) this was eventually resolved with either an Equivalent Level of Safety (ELoS) or Alternate Method of Compliance (AMoC). I expect the same will be done for the 777X