AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
Cessna 400 Series Aeroplanes
AD/CESSNA 400/118
Auxiliary Wing Spars
4/2009 DM
 
Applicability:
Model 401 aircraft, serial numbers 655 and 401-0001 through 401-0322.
Model 401A aircraft, serial numbers 655 and 401A0001 through 401A0132.
Model 401B aircraft, serial numbers 401B0001 through 401B0221.
Model 402 aircraft, serial numbers 402-0001 through 402-0322.
Model 402A aircraft, serial numbers 402A0001 through 402A0129.
Model 402B aircraft, serial numbers 402B0001 through 402B0122, 402B0201 through 402B0249, 402B0301 through 402B0455, 402B0501 through 402B0640, 402B0801 through 402B0935, 402B1001 through 402B1100, 402B1201 through 402B1250, and 402B1301 through 402B1384.

Requirement:
Visually inspect the auxiliary wing spar near the location where the main landing gear trunnion is mounted, for cracks; in accordance with Cessna Service Bulletin
MEB08-8 original issue, or later FAA approved revision.
If any crack is detected during any inspection that is 0.5-inch or more, before further flight, replace the cracked part(s).
If any cracks are detected during any inspection that are less than 0.5-inch, accomplish the following:
Repetitively inspect the crack(s) for length at intervals not to exceed 50 hours time in service and, before further flight, replace any part that has a crack with a length of 0.50-inch or more; and,
Replace the cracked part within 200 hours time in service after the original crack was detected, or within 12 months after the original crack was detected, whichever occurs first.
If cracks are detected as a result of any inspection, report the results to the Cessna Aircraft Company at whichever of the following occurs later:
Within 10 days after the inspection is accomplished; or,

 
 
Within the next 10 days after 2 March 2009.
Note 1:  Supplemental Inspection Numbers 57-10-09 and 57-10-13 of the Cessna 401/402 Supplemental Inspection Document (SID) inspect the auxiliary spar caps, but not the webs.  Hence, this Airworthiness Directive applies even to SID-compliant aircraft.
Note 2:  FAA AD 2009-04-04 Amdt 39-15810.

Compliance:
Accomplish the initial inspection within 10 hours time in service after 2 March 2009, unless already accomplished; and, in addition, before further flight anytime the aircraft experiences a hard landing.  Inspect thereafter if cracking is detected, as specified in the Requirement section of this Directive.

 
This Airworthiness Directive becomes effective on 2 March 2009.

Background:
The FAA received several reports of fatigue cracking on Models 402A and 402B aircraft, in the area of the auxiliary wing spar where the main landing gear trunnion is mounted.  This condition, unless corrected, could result in failure of the wing auxiliary spar web and cause landing gear collapse during normal landing.  This could lead to loss of control and passenger injury.

David Villiers
Delegate of the Civil Aviation Safety Authority
23 February 2009