The FAA has denied Bell Helicopter’s petition for an exemption to the normal category Part 27 weight limit of 7,000 pounds for the Bell 429 light twin to 7,500 pounds, but plans to seek public comment that could lead to a revision of Part 27 standards.

Transport Canada and a dozen other countries granted the exemption earlier this year. The FAA’s move is seen as a major setback, at least in the short term, for Bell’s ability to market the 429 as an IFR EMS aircraft in the U.S. With a full medical interior, the 429 has an average empty weight of 5,100 pounds, limiting its IFR range with patient, pilot and two EMS crew aboard.

Bell developed an increased gross weight (IGW) package that requires operators to install a $115,000 kit that includes CVR/FDR, radar altimeter, HTaws and strobe lights to meet several of the more stringent Part 29 (over 7,000 pounds) transport category requirements. However, despite the equipment upgrades, the FAA refused to grant the weight exemption on multiple grounds, one of which was its belief that such an exemption would give Bell an unfair market advantage and upset FAA-EASA “harmonization.” The FAA held open the possibility that Part 27 weight limits could be reassessed in the future.

Writing for the FAA, Kimberly Smith, manager of the rotorcraft directorate aircraft certification service, noted that European OEMs and the EASA formally objected to granting Bell the exemption and also that it is a generally accepted aviation principle to require more stringent levels of aircraft safety as max takeoff weight increases. “Currently, rotorcraft that exceed [a maximum of] 7,000 pounds are expected to meet a higher level of safety prescribed by Part 29, transport category rotorcraft. To allow a rotorcraft to be certified at a higher weight than allowed by the regulations undermines the very philosophy that has served the United States aviation community since the beginning.”

Smith acknowledged that technological changes might have made current certification weight standards under Part 27 obsolete, but commented that granting an exemption is not the best way to address the issue. “Any change to the current philosophy of rotorcraft airworthiness standards needs to be done in a public forum. Therefore, the FAA will issue a notice in the future to seek public input as to whether there are more appropriate certification focus areas, such as ‘technical complexity and safety’ as suggested by Bell Canada.”

A Bell spokeswoman said the company plans to appeal the FAA ruling. “The FAA’s decision is disappointing. We have requested a meeting with the FAA to discuss its decision.”

“The Bell 429 is limited by regulation, not capability,” said the Bell spokeswoman. “After an extensive technical evaluation of the safety and operational requirements, Transport Canada–the certifying authority for the aircraft and a bilateral partner with the FAA–approved operation of the Bell 429 at 7,500 pounds. Transport Canada’s findings, which included extensive flight testing, ground tests and engineering analysis, were shared with the FAA.”