2005-16-09: Flappers.

2005-16-09 Learjet: Amendment 39-14214. Docket No. FAA-2005-20798; Directorate Identifier 2004-NM-257-AD. Effective Date (a) This AD becomes effective September 13, 2005. Affected ADs (b) This AD supersedes AD 95-25-03, amendment 39-9447. Applicability (c) This AD applies to the airplanes in Table 1 of this AD, certificated in any category. Table 1.--Applicability Learjet Serial numbers Model 23 airplanes..................................................... 23 003 through 23 090 inclusive. Model 24 airplanes .................................................... 24 100 through 24 357 inclusive. Model 25 airplanes ................................................... 25 002 through 25 373 inclusive. Model 35 airplanes ................................................... 35 002 through 35 676 inclusive. Model 36 airplanes ................................................... 36 002 through 36 063 inclusive. Unsafe Condition (d)This AD results from numerous continual inspections and the approval of a new, improved flapper and flapper assembly. We are issuing this AD to prevent significant reduction in the lateral control of the airplane due to imbalance of the fuel loads in the wings of the airplane. Compliance (e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. Requirements of AD 95-25-03 Repetitive Inspections, Related Investigative Actions, and Replacement (f) Within 50 hours time-in-service after December 27, 1995 (the effective date of AD 95-25-03), or prior to the accumulation of 600 hours time-in-service since installation of the flapper valve, whichever occurs later: Perform an inspection to detect deterioration (such as cracks, cuts, breaks, splits, or warpage) of both flappers of the tip tank in each wing, in accordance with either Learjet Service Bulletin SB 23/24/25-28-2, dated October 6, 1995 (for Model 23, 24, and 25 airplanes); or Learjet Service Bulletin SB 35/36-28-10, dated October 6, 1995 (for Model 35 and 36 airplanes); as applicable. Repeat this inspection thereafter at intervals not to exceed 600 hours time-in-service. (1) If no deterioration of the flapper valve is detected, prior to further flight, inspect the flapper valve to ensure proper positioning, inspect the condition of the screws that retain the flapper valve to the plate assembly to ensure that the flapper valve is secure, inspect to ensure that the flapper valve completely covers the opening of the tube and is seated against the tube, and inspect the flapper valve to verify that it moves freely; and accomplish the follow-on corrective actions, if any discrepancy is found. These actions shall be accomplished in accordance with the applicable service bulletin. (2) If any flapper valve is found to be deteriorated, prior to further flight, replace it with a new flapper valve in accordance with the applicable service bulletin. (g) Except as provided in paragraph (h) of this AD, at the later of the times specified in paragraphs (g)(1) and (g)(2) of this AD: Replace both flappers of the tip tank in each wing with new flappers in accordance with either Learjet Service Bulletin SB 23/24/25-28-2, dated October 6, 1995 (for Model 23, 24, and 25 airplanes); or Learjet Service Bulletin SB 35/36-28-10, dated October 6, 1995 (for Model 35 and 36 airplanes); as applicable. (1) Within 5 years since date of installation of the flapper valve, or prior to the accumulation of 2,400 total hours time-in- service on the flapper valve, whichever occurs earlier. (2) Within 50 hours time-in-service after December 27, 1995. (h) For airplanes on which the age and time-in-service of the flapper valve cannot be determined: Within 50 hours time-in-service after December 27, 1995, replace both flappers of the tip tank in each wing in accordance with either Learjet Service Bulletin SB 23/ 24/25-28-2, dated October 6, 1995 (for Model 23, 24, and 25 airplanes); or Learjet Service Bulletin SB 35/36-28-10, dated October 6, 1995 (for Model 35 and 36 airplanes); as applicable. (i) Within 600 hours time-in-service following replacement of any flapper valve in accordance with the requirements of this AD, and thereafter at intervals not to exceed 600 hours time-in-service: Accomplish the requirements of paragraph (f) of this AD. New Requirements of This AD Inspection and Replacement (j) Within 600 hours time-in-service since last replacement of any flapper valve in accordance with the requirements of this AD, or within 90 days after the effective date of this AD, whichever occurs later, inspect the flappers and flapper assemblies of the tip tank in each wing to determine their part numbers (P/N). The raised letter and numbers "S-461" on the convex side of the flappers can identify these parts. Instead of inspecting the flappers and flapper assemblies, a review of airplane maintenance records is acceptable if the P/N of the flappers and flapper assemblies can be conclusively determined from that review. (1) If four flappers having P/N 2323006-802 and four flapper assemblies having P/N 2323006-801 are found installed, no further action is required by this paragraph, and the repetitive inspections required by paragraphs (f) and (i) of this AD can be stopped. (2) If any flapper having P/N 2323006-5 or any flapper assembly having P/N 2323006-6 is found installed, within 600 hours time-in- service since last replacement of any flapper valve in accordance with the requirements of this AD, replace the flapper valve with a new flapper valve or replace the flapper assembly with new or modified and reidentified assembly, as applicable. The replacement must be done in accordance with the Accomplishment Instructions of Bombardier Service Bulletin SB 23/24/25-28-7, Revision 2, dated May 9, 2001 (for Model 23, 24, and25 airplanes); or Bombardier Service Bulletin SB 35/36-28-14, Revision 2, dated May 9, 2001 (for Model 35 and 36 airplanes); as applicable. Accomplishment of the replacement ends the repetitive inspections required by paragraphs (f) and (i) of this AD. Parts Installation (k) As of the effective date of this AD, no person may install a flapper having P/N 2323006-5 or a flapper assembly having P/N 2323006-6, on any airplane. Alternative Methods of Compliance (AMOCs) (l)(1) The Manager, Wichita Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. (2) AMOCs approved previously according to AD 95-25-03 are not approved as AMOCs with this AD. Material Incorporated by Reference (m) You must use the applicable service bulletins identified in Table 2 of this AD to perform the actions that are required by this AD, unless the AD specifies otherwise. (1) The Director of the Federal Register approved the incorporation by reference of Bombardier Service Bulletin SB 23/24/ 25-28-7, Revision 2, dated May 9, 2001; and Bombardier Service Bulletin SB 35/36-28-14, Revision 2, dated May 9, 2001; in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. (2) On December 27, 1995 (60 FR 63617, December 12, 1995), the Director of the Federal Register approved the incorporation by reference of Learjet Service Bulletin SB 23/24/25-28-2, dated October 6, 1995; and Learjet Service Bulletin SB 35/36-28-10, dated October 6, 1995. (3) Contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html . TABLE 2. MATERIAL INCORPORATED BY REFERENCE Service bulletin Revision level Date Bombardier Service Bulletin SB 23/24/25 28 7 ............... 2 ............................... May 9, 2001. Bombardier Service Bulletin SB 35/36 28 14 ................. 2 ............................... May 9, 2001. Learjet Service Bulletin SB 23/24/25 28 2........................... Original .................... October 6, 1995. Learjet Service Bulletin SB 35/36 28 10.............................. Original .................... October 6, 1995.