Jets Under 6,000 Pounds Would No Longer Be Excluded From Function And Reliability Testing

The FAA has published a Notice of Proposed Rulemaking (NPRM) that would revise the applicability for function and reliability flight testing to include all turbine-powered airplanes weighing 6,000 pounds or less. The FAA says revising the applicability is necessary because advancements in aviation technology have invalidated the reasons for excluding these airplanes, and that the proposed revision would improve aviation safety for the category.

Function and reliability (F&R) flight testing simulates typical aircraft, in-service flight operations for a new aircraft design. This flight testing is done prior to the aircraft's final design approval leading to the issuance of a TC. The F&R flight testing requirement in Sec.  21.35(b)(2) gives the FAA and the public a reasonable assurance that an aircraft, its components, and its equipment are reliable and function properly.

The FAA says that, after reviewing several recent TC projects for small turbojet-powered airplanes (turbojets) involving airplanes expected to weigh 6,000 pounds or less, it determined that most, if not all, of these airplane designs would benefit from the F&R flight testing requirement. This determination is based on new lightweight, turbine-powered airplanes having design features and performance consistent with larger airplanes that are required to undergo F&R flight testing.

The NPRM document states that the decision to exclude certain airplanes of 6,000 pounds or less maximum weight from F & R flight testing was based on the state of technology existing in 1950. Recent FAA TC program experience with the new very light jets (VLJ) has led to reconsideration of the existing exclusion of airplanes weighing 6,000 pounds or less in Sec. 21.35(b)(2). This reconsideration was driven in part by difficulties encountered with the voluntary application of the requirement during the FAA type certification of the Eclipse Aviation Corporation's (Eclipse) EA-500 VLJ and the subsequent problems experienced during that airplane's entry into service.

Eclipse 500 First Flight 2002

After reviewing the Eclipse SCR and the EA-500 certification program, the FAA reviewed the likelihood that F&R flight testing requirements might have preventatively identified problems encountered by the EA-500 when it entered into service. Function and reliability flight testing might have discovered five of the problems identified in the SCR (pitch and rudder trim problems; pitot system moisture trap; engine surges caused by hard carbon build-up on the static vanes; brake problems; and tire problems) while two of the cited problems (autopilot turbulence sensitivity; and problems with the software logic dealing with the throttle position) would less likely have been detected, based on the chances of duplicating causal conditions and other risk factors. These conclusions were based on the likelihood that the root causes for the reported problems would be identified by the additional effective flight testing that would be accomplished by a mandatory F&R flight testing program (150 or 300 additional hours of simulated in-service operations accomplished in various environments and locations). The FAA says the criteria for selection of 150 or 300 hours is not changed in this proposal. They estimate that F&R testing will cost $317,066 for a 165-hour program and $634,132 for a 330-hour program.

The FAA invites interested persons to participate in this rulemaking by submitting written comments, data, or views. Comments relating to the economic, environmental, energy, or federalism impacts that might result from adopting the proposals in this document are also solicited. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data.

Comments on the NPRM are due on or before July 8, 2010.

FMI: http://edocket.access.gpo.gov/2010/2010-8130.htm