Owner Organizations Collecting Usage Data
Several owner groups have joined forces to create a new web
site, http://twin.cessna.org,
to collect usage data for Cessna 300- and 400-series piston twins.
The FAA wants this data in order to assess the impact of its
proposed Airworthiness Directives that would mandate the
installation of a very costly spar strap modification on these
aircraft, while the owner groups are hoping that the data will help
make the case for substantially relaxing the compliance times that
the FAA has proposed (as low as 5,500 hours for some affected
models.
Hosted by the Cessna Pilots Association and co-sponsored by the
Cessna Twins Spar Corp, the Twin Cessna Flyer, the Aircraft Owners
and Pilots Association (AOPA) and the Regional Air Cargo Carriers
Association (RACCA) with encouragement from the FAA, the new web
site has been created to collect accurate fleet usage data from
owners and operators of twin Cessnas, and to build a realistic
picture of how twin Cessna aircraft are flown today. The site also
contains an extensive library of information about the FAA's
proposed rulemaking action, and an open forum where owners and
other interested parties can ask questions and exchange ideas.
"Metal fatigue is cumulative in aluminum structures such as the
wing spar, and is exquisitely sensitive to actual flight usage
patterns," said John Frank, executive director of the Cessna Pilots
Association. "We are concerned that the operational assumptions
used by Cessna Aircraft Company and the FAA to establish the
compliance times in the proposed ADs may have been unrealistically
pessimistic, and we hope that the operator-furnished data we are
collecting will show that the compliance times for the proposed
wing spar ADs can be extended, perhaps substantially. The FAA and
Cessna presented information at a meeting held in Washington D.C.
on March 3 and 4, 2004, supporting the need for a spar strap
modification for Cessna 401, 402, 411 and 414A models, and
suggesting that similar ADs might soon be in the works for
additional Cessna 300- and 400-series models..
"The safe fatigue life of these wing
spars is very dependent on how the plane has been loaded and flown
over its life," said Bob Vila, president of the Cessna Twins Spar
Corp. "The load and flight profile assumptions used by Cessna in
developing their fatigue life calculations reflect Cessna 402
aircraft used for sightseeing and Part 135 charter operations that
have very heavy cabin loads and very severe duty cycles compared to
the life of a typical Part 91 airplane flown for personal use."
According to Twin Cessna Flyer president Larry Ball, "It's
vitally important that all owners and operators of all of twin
Cessna aircraft visit this site to record their actual aircraft
history and operational usage patterns. We believe that the
collection of this data will help the FAA to determine that twin
Cessna aircraft have lived a much kinder life than the severe usage
patterns than Cessna and the FAA currently use to model the entire
fleet."
Once collected, this fleet usage
data will be used to develop fatigue life models that may
ultimately lead to the extension of the compliance times for the
aircraft currently affected by the proposed ADs and lead to a
better understanding of how the entire fleet of 300 and 400 series
are flown. These results will be presented at the FAA's
follow-on public meeting about the proposed ADs expected to take
place sometime this summer. The Cessna Pilots Association plans to
use the survey data to develop a recommended implementation plan
intended to minimize the impact on owners, and the Cessna Twins
Spar Corp. plans to combine the survey data with its engineering
efforts to collect actual in-flight test data.
The sponsoring owner organizations are also concerned that many
owners and operators of Cessna 300- and 400-series airplanes are
still not aware of the enormous impact that the proposed ADs would
have on their aircraft. Consequently, the new web site at http://twin.cessna.org is designed to
be a definitive resource where twin Cessna owners and
operators can obtain all of the latest information relevant to the
proposed wing spar ADs and can ask questions and conduct relevant
discussion with industry experts and fellow
owners/operators.
FMI: http://twin.cessna.org