By David Learmount in London
US agency raises the bar for certification of new rotorcraft types to reflect advances in handling performance
New-build helicopters must meet higher standards of flyability, controllability and stability, says the US Federal Aviation Administration in a notice of proposed rulemaking (NPRM). The FAA says it has been talking to the European Joint Aviation Authorities since 1994 about the need to raise the certification bar because modern helicopters are capable of higher standards than are demanded under present certification regulations.
Comment on the standards proposed has to be filed by 23 October, says the NPRM - a relatively short period that the FAA justifies by referring to its extensive consultation with industry and harmonisation talks with Europe. The rules will apply to normal category helicopters certificated under FAR Part 27 and transport category aircraft under Part 29.
Certification is about determining the limits of a helicopter's operating envelope, and that remains the case, but the message stated repeatedly in the NPRM against each required manoeuvre or flight phase at maximum weight, altitude or temperature limit indicates that it "may not require exceptional piloting skill or exceptionally favourable conditions". This would apply to Part 27 aircraft - including piston-powered machines - as well as Part 29 helicopters.
The FAA's thinking is illustrated in its proposed requirements for controllability and manoeuvrability in Part 29 helicopters, for example: "Wind velocities from zero to at least 17kt [30km/h], from all azimuths, must be established in which the rotorcraft can be operated without loss of control [in and out of ground effect] in any manner appropriate to the type, such as crosswind take-offs, sideward flight and rearward flight, while at critical weight, critical centre of gravity, critical rotor RPM and altitudes from standard sea level conditions to the maximum take-off and landing altitude capability of the rotorcraft."
Requirements for static longitudinal and directional stability are being heightened, and although this is not specifically related to the FAA's requirements for instrument flight rules capability, the agency makes clear that instrument flight must be far easier for the pilot. The NPRM also says that "a means to restart" a stopped or flamed-out engine would also be a requirement for all types.
Source: Flight International
