Icon Aircraft must supply significantly more data about the A5 amphibian before the US Federal Aviation Administration (FAA) will consider a long-standing request for a weight exemption.

In a 2 May letter to the Los Angeles, California-based start-up, the FAA finally responded to Icon's year-old request, but did not provide a firm answer.

Icon first applied on 7 May 2012 to be exempted from the 649kg (1,430lb) weight limit for a special-light sport aircraft. The A5 needs the exemption because it uses a spin-resistant airframe. It is a feature that is intended to improve safety, but means the A5 will exceed the FAA's weight limit under the S-LSA category without the exemption, Icon says.

But the FAA's manager of the small airplane directorate in Kansas City, Missouri wrote to in the 2 May letter to Icon that its request would be "precedent-setting". As a result, the agency needs more time and information to process the company's request.

The FAA is compelled by the regulatory statute to consider weight exemptions when they have the potential to improve safety, but agency officials have been reluctant in the past to approve such applications.

Last September, the FAA rejected Bell Helicopter's request for a weight exemption for the Bell 429 medium-twin helicopter, despite a previous approval by Transport Canada. In its rejection letter, the FAA reasoned that exempting the 429 would put its rivals at a competitive disadvantage for remaining within the weight limits.

Approving a similar exemption for the A5 could face similar questions. The Independent Aircraft SeaDragon, for example, was designed to meet the S-LSA weight limit for which the A5 is seeking an exemption.

The regulatory issue adds to Icon's development issues. The introduction of the A5 is already four years behind schedule. Icon already started releasing design drawings for the fuselage in January, allowing production to begin on an aircraft that has not yet cleared all of its certification questions.

Source: Flight International