FAA: This AD is effective May 20, 2013.
We are adopting a new airworthiness directive (AD) for all
The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series
airplanes. This AD was prompted by reports of an incorrect procedure used to
apply the wear and corrosion protective surface coating to attach pins of the
horizontal stabilizer rear spar. This AD requires inspecting to determine the
part number of the attach pins of the horizontal stabilizer rear spar, and
replacing certain attach pins with new, improved attach pins. We are issuing
this AD to prevent premature failure of the attach pins, which could cause
reduced structural integrity of the horizontal stabilizer to fuselage
attachment, resulting in loss of control of the airplane.
We estimate that this AD affects
1,050 airplanes of U.S. registry.
We estimate the following costs to
comply with this AD:
Estimated
Costs
|
Action
|
Labor
cost
|
Parts
cost
|
Cost
per product
|
Cost
on U.S. operators
|
Inspection and attach pin
replacement
|
39 work-hours × $85 per hour =
$3,315
|
Up to $6,312
|
$9,627
|
Up to $10,108,350.
|
According to the manufacturer, some
of the costs of this AD may be covered under warranty, thereby reducing the
cost impact on affected individuals. We do not control warranty coverage for
affected individuals. As a result, we have included all costs in our cost
estimate.
Applicability
(1) This AD applies to all The
Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series
airplanes, certificated in any category.
(2) Installation of Supplemental
Type Certificate (STC) ST00830SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se)
does not affect the ability to accomplish the actions required by this AD.
Therefore, for airplanes on which STC ST00830SE is installed, a “change in
product” alternative method of compliance (AMOC) approval request is not
necessary to comply with the requirements of 14 CFR 39.17. For all other AMOC requests, the
operator must request approval for an AMOC in accordance with the procedures
specified in paragraph (k) of this AD.
Unsafe
Condition
This AD was prompted by reports of
an incorrect procedure used to apply the wear and corrosion protective surface coating
to attach pins of the horizontal stabilizer rear spar. We are issuing this AD
to prevent premature failure of the attach pins, which could cause reduced
structural integrity of the horizontal stabilizer to fuselage attachment,
resulting in loss of control of the airplane.
Part
Number (P/N) Inspection
For airplanes having line numbers 1
through 3534 inclusive: Before the accumulation of 56,000 total flight cycles,
or within 3,000 flight cycles after the effective date of this AD, whichever
occurs later, inspect to determine the part number of the attach pins of the
horizontal stabilizer rear spar. A review of airplane maintenance records is
acceptable in lieu of this inspection if the part number of the attach pin can
be conclusively determined from that review.
Replacement
If, during the inspection required
by paragraph (g) of this AD, any horizontal stabilizer rear spar attach pin has
P/N 180A1612-3 or 180A1612-4, prior to the accumulation of 56,000 total flight
cycles on the pin, or within 3,000 flight cycles after the effective date of
this AD, whichever occurs later, replace with a new attach pin having P/N
180A1612-7 or 180A1612-8, respectively, in accordance with the Accomplishment
Instructions of Boeing Special Attention Service Bulletin 737-55-1093, dated
April 9, 2012.