IT APPEARS that the European and US authorities have reached agreement over "grandfather rights" in the certification of derivative airliner types. Now all they have to do, is agree their respective interpretations over what is a grandfather right and what is a derivative, which may be a little more difficult, if they are not to lose sight of the fact, that this whole argument is about the raising, rather than compromising, of safety standards.

The disagreement between the European Joint Airworthiness Authorities (JAA) and the US Federal Aviation Administration over how they should treat derivatives was never really going to blow into a full-scale dispute, simply because the industry cannot afford to have the world's two major certification authorities at odds with each other. There were the makings of a far more major dispute between the world's two major airliner manufacturers, however, simply because one (Airbus, with its A319/320/321 family) felt that it was being seriously disadvantaged by the FAA's proposed treatment of the other (Boeing, with its next generation 737).

The issue of so-called grandfather rights is a complex one in which the advance of certification standards must be balanced against the march of technology and the reality of commerce. On one hand, a manufacturer should not be penalised just because it has a successful model, which stays in production with minor improvements over a great many years. On the other, a manufacturer which invests in a totally new model should not be disadvantaged by having to certificate that model to much higher standards than those imposed on the much-improved older competitor.

The first needs to be protected from what would, in effect, be retrospective legislation imposing standards undreamt of when the aircraft was first designed. The second needs to be protected from the effects of being perhaps the only manufacturer facing the cost of meeting those new standards. Most importantly, however, the passenger needs to be protected from the possible ill effects of either side being granted too many exemptions on commercial grounds.

The new agreed approach seems to offer a much safer middle ground, in which a manufacturer seeking to certificate under grandfather rights would have to justify the inclusion of each major component of the aircraft in that exemption, rather than being able to claim exemption for the whole. Thus, a manufacturer offering an aircraft with a new wing on an existing fuselage might have to seek new-standard certification for the wing, while carrying over previous certification for the fuselage. (That, of course, might offer little comfort to Airbus, whose principal objection to the proposed grandfather certification of the new 737 is that Boeing could offer more seats on its old fuselage than Airbus can on its newer one for the same number of exits.)

This is the area of potential weakness in the new proposal: the argument may simply move from being a global one over who has grandparents to a multi-faceted one over how many grandparents each side has.

That said, the overall aim of the new proposal seems to be that each part of an aircraft will have to be certificated to the most recent requirement which can be practicably applied to that part, rather than to the requirement in force when the parent airframe was first designed. Interpretations of what can be practicably applied will doubtless have no bounds, and the resolution of those interpretations will be a measure of the sincerity of the two regulators' intentions and resolve to have a genuinely common international set of certification standards.

Their success will, in large part, depend on the willingness of the manufacturers to accept and abide by the agreements reached between the regulators, and to not to seek more advantageous interpretations from their respective home bodies. It is the credibility of the industry at stake here - and nobody wants to see that endangered by an incident in which a customer is hurt because an airliner was certificated to a standard lower than the highest practically achievable.

Source: Flight International