Sir - You raise the subject of the application of old certification standards to new-derivative aircraft such as the Boeing 737X (Flight International, 10-16 May).
We understand that some new standards apply only to new designs, and may not be appropriate for an existing, well-proved aircraft. For example, requiring an aircraft structure to comply with damage-tolerance criteria.
We wonder whether an aircraft can be considered an old design when it has a new wing, new engines and new avionics.
More significant are new rules which could be applied whatever the design: such as the method of computing the payload an aircraft can lift off a given runway (Amendment 42), or the number of seats which can be installed in relation to size and the number of exits.
Either such improvements are real safety enhancements, and apply to everybody, or they are recognised as worthless. We should be allowed to re-certificate our take-off performance and our maximum seat layout.
Different yardsticks should not be used to measure the value of similar designs.
ROBERT ALIZART
Vice-president corporate communications
Airbus Industrie, Toulouse, France
Source: Flight International
