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.