Bell Helicopter has petitioned the US Federal Aviation Administration to reconsider the agency's decision to deny an exemption from a gross weight limit for the Bell 429.
The appeal comes after the company's warning that the market for the Bell 429 could be substantially reduced in the USA if the FAA upholds its decision in August to restrict the medium-twin to a 3,175kg (7,000lb) weight limit under Part 27 safety standards.
The FAA will open a 120-day comment period that begins on 18 December, allowing the public and Bell's competitors to submit views and information about the petition.
Bell argued when it applied for the 227kg exemption from the Part 27 weight limit that the standard forces operators to fly the Bell 429 with fewer passengers or safety equipment.
But Bell's competitors, including AgustaWestland, opposed Bell's request for an exemption, saying it would create an unfair advantage for the Bell 429.
The FAA sided with the competitors' argument and denied Bell's request for exemption.
That decision put US regulators at odds with several airworthiness authorities that have already approved the request for the Bell 429 exemption. Transport Canada approved the original exemption request submitted by Bell Helicopter, which manufactures the Bell 429 near Montreal.
Bell Helicopter has already delivered examples of the increased gross weight Bell 429 under the Transport Canada exemption. But the FAA's denial means Bell Helicopter cannot deliver aircraft that do no meet the Part 27 weight limit to customers in the US market, which must continue to operate the lighter weight version of the aircraft.
European airworthiness authorities have not yet ruled on Bell Helicopter's request for an exemption.
Without an exemption, the higher-weight Bell 429 would have to be certified at the Part 29 standards, which adds requirements for flaw-tolerant rotor blades and more stringent bird strike conditions.