Toro-Southwest Airlines 2009

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U.S.Department of Transportation Federal Aviation Administration OCT 1 9 2009 Southwest Airlines Co.

Christian Toro DAL2MX 2832 Shorecrest Drive Dallas, TX 75235

Dear Mr. Toro:

Office of the Chief Counsel 800 Independence Ave., S.w.

Washington, D.C. 20591 This letter is in response to your request for interpretation of Title 14 of the Code of Federal Regulations (14 CFR), section 121. 139(b), Requirements for manual aboard aircraft: Supplemental operations. In your letter, dated June 15,2009, you requested clarification of the circumstances under which a part 121 certificated air carrier would meet the requirements of section 121.139(b) in order to be exempt from the requirements of section 121. 139(a).

Section 121. 139(a) requires, in pertinent part, that each certificate holder conducting supplemental operations carry the appropriate parts of its manual on each airplane when away from its principal base of operations. Those parts must be available for use by ground or flight personnel. The exception to this rule, in § 121.13 9(b), states that if a certificate holder conducting supplemental operations is able to perform all scheduled maintenance at specified stations where it keeps maintenance parts of its manual, that certificate holder is not required to carry those parts of the manual aboard the aircraft en route to those stations. According to your letter Southwest Airlines conducts scheduled operations pursuant to 14 CFR 119.21(a)(I)--Domestic. Southwest also conducts supplemental operations in accordance with Part 121 operating requirements. Pursuant to paragraph C070 of Southwest's operations specifications, Airports Authorized for Scheduled Operations, Regular Airports, Southwest conducts scheduled maintenance activity at the following stations:

(1) line stations where maintenance and minor repairs are performed by contractors, (2) maintenance stations that are staffed by SWA maintenance personnel capable of performing all levels of maintenance, up to and including A and MV checks as well as minor repairs, and (3) maintenance bases where Southwest personnel perform all levels of maintenance, including heavy maintenance as well as major repairs and alterations.

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Your letter states that Southwest's operational procedures and contractual obligations require it to perform scheduled maintenance only at those stations identified in its operations specifications. You state further that Southwest will not perform scheduled maintenance at any other locations, and it does not conduct scheduled maintenance during supplemental operations. Though not specifically stated, I assume from your letter that Southwest's maintenance manuals are located at the stations where scheduled maintenance will be performed, i.e. those stations listed above in the C070 operations specification. You suggest that the manuals should not be required aboard the aircraft during a supplemental operation because maintenance is not anticipated during those operations. For these reasons, you question whether Southwest meets the requirements of section 121.13 9(b) and is therefore exempt from the requirements of 121.139(a). These facts alone do not give rise to an exception from section 121.139(a). Section 121.139(b) provides the certificate holder with an exception to the maintenance manual requirement when the aircraft is en route to those stations where the certificate holder keeps maintenance parts of the manual, such that scheduled maintenance could be performed at that location. Accordingly, Southwest would be exempt from the requirements of 121.139(a), and not required to carry the maintenance portion of its manual aboard the aircraft, only when it is conducting a supplemental operation en route to a station where the maintenance parts of its manual are kept. In your scenario, the maintenance manuals would be required aboard the aircraft during supplemental operations into destinations not listed in the C070 operations specifications.

We trust that this interpretation responds satisfactorily to your question. This response was prepared by Angela Washington, attorney in the Regulations Division, Office of the Chief Counsel, and coordinated with the General Aviation and Commercial Division of the Flight Standards Service. If you have further questions, please contract my staff at 202-267-3073.

Sincerely,

puv--~,,-)v;J Rebecca B. M:c"~rson Assistant Chief Counsel for Regulations, AGC-200