AD 86-11-01 R1

86-11-01 R1 BOEING: Amendment 39-5322 as amended by Amendment 39-5550. Applies to all Model 747 airplanes, certificated in any category. To prevent wheel or tire failure as a result of failure of the wheel bearing, accomplish the following, unless already accomplished:

A. Within 100 flight cycles after the effective date of this AD, remove and inspect both the inner and outer wheel bearings, Timken P/N's LM229146 and LM229139, in accordance with the applicable portions of Sections 32-45-01 through 32-45-03 of the Boeing Model 747 maintenance manual. Any wheel bearing found damaged must be replaced with a new or serviceable bearing prior to further flight.

NOTE: Serviceable bearings are those Timken bearings, P/N's LM229146 and LM229139, which have been inspected with a close visual inspection and found to have no visible damage (i.e., galling, gouging, spalling, overheat, etc.).

B. After accomplishment of the inspection required by paragraph A., above, reinspectboth the inner and outer wheel bearings in accordance with the schedule below. Any wheel bearing found damaged as a result of the required inspections must be replaced with a new or serviceable bearing before further flight.

1. Bearings P/N LM229146 and LM229139, date stamped LS and subsequent, except those identified in subparagraph B.2., below, must be reinspected at intervals not to exceed 100 flight cycles.

2. Bearings date stamped LS and subsequent, which are installed on Boeing Model 747SR airplanes which have not incorporated Boeing Service Bulletin 747-32-2272 (which relates to gross weight increase), must be reinspected at intervals not to exceed 200 flight cycles.

C. Installation of inner and outer Timken wheel bearings, P/N's LM229147C and LM229140C, constitutes terminating action for the repetitive inspections required by paragraph B., above.

D. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable levelof safety, may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.

E. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate an airplane to a base for the accomplishment of inspections and/or modifications required by this AD.

The service information specified in this AD may be obtained upon request to the Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. It may also be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.

Amendment 39-5322 became effective June 13, 1986. This amendment, 39-5550, becomes effective February 26, 1987.