For European operations, Alert Height is described in
CS AWO. With recent transatlantic harmonization of requirements, I would expect the FAA interpretation to be similar, or approve the manufacturer’s recommended operation.
CS-AWO 312:-
For a fail-operational system with a decision height below 15 m (50 ft) or with no decision height, an alert height must be established in accordance with CS–AWO 365(a) and must be at least 30 m (100 ft). Max alert height should not be greater than 300ft.
Concept, CS-AWO 300:-
The alert height is a specified radio height, based on the characteristics of the aeroplane and its fail-operational landing system. In operational use, if a failure occurred above the alert height in one of the required redundant operational systems in the aeroplane (including, where appropriate, ground roll guidance and the reversionary mode in a hybrid system), the approach would be discontinued and a go-around executed unless reversion to a higher decision height is possible. If a failure in one of the required redundant operational systems occurred below the alert height, it would be ignored and the approach continued.
Thus the question of the failure of FLARE at 30 ft should not occur (reliability 10-9?).
As most fail-operational certifications are aircraft specific, it might be expected that the alert height and crew procedures are also type related. Thus, aligning procedures with other aircraft types might be unwise. However, a change or deletion of a call might be approved by a national authority provided the procedures before and after alert height are clearly understood and meet the basis of the aircraft certification. Any change would be a function of training and SOP, however all changes should be verified by the manufacturer to check that nothing essential has been overlooked.
The term is also mentioned in JAR-OPS 1 Subpart E under ‘Fail-Operational flight control System’ (as CS AWO 300);training requirements are stated.