Models 600 S2D, S2R and S-2R series aircraft, as listed in FAA AD
2006-07-15 that do not have a part number 22507 lower spar cap
incorporated on both the left and right wings.
Requirement: Inspect the wing main spar lower
caps in accordance with the technical requirements of FAA AD
2006-07-15 Amdt 39-14542.
Note 1: Ayres Service Bulletin No. SB-AG-39, Ayres Custom Kit
No. CK-AG-29, and Quality Aerospace Custom Kit No. CK-AG-30
Note 2: The Requirement document can be obtained through the FAA
web site, www.faa.gov/aircraft/safety/alerts/,
or by contacting firstname.lastname@example.org
Compliance: As specified in the Requirement
document, with a revised effective date of 2 May 2006.
This Amendment becomes effective on 2 May 2006.
Background: The original issue of this AD was
raised following a wing spar fatigue failure accident in Holland,
and initial inspections that found two Australian aircraft with
Amendment 1 was raised
following a wing spar fatigue failure accident in the USA, the
inspection results of the original issue, which revealed more
aircraft with spar cracks, and a reassessment of compliance data.
The FAA issued an AD requiring a once-only inspection as an interim
measure. Both CASA and the Dutch authority, the RLD, instituted
repetitive inspections. Amendment 1 was subject to review upon
receipt of further information
Amendment 2 reflected the next FAA AD which took into account
the service cracking experienced, and aircraft weight and
configuration, and included repetitive inspections.
Amendment 3 retained the repetitive inspections and replacement
(if necessary) requirements of the lower spar caps that are
currently required by the previous AD, adds additional aircraft to
applicability, and adds a third repair option. Amendment 4 is
issued in response to a new FAA AD, which was issued as a result of
the analysis of data from 112 cracks found in the last 8 years on
similar design Model 600 S2D, S2R and S-2R series aircraft; and
FAA’s determination that an immediate initial inspection and
more frequent repetitive inspections are necessary for certain
aircraft. Consequently, this Directive requires an increase in
frequency of the repetitive inspections for certain aircraft, and a
decrease for others. Undetected fatigue cracks could result in
lower wing spar cap failure, and consequent loss of a wing.