Airworthiness Directive · Amendment 39-11906 · Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes
Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes; line numbers 1 through 2939 inclusive; certificated in any category.
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c)(1) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This document corrects information in an existing airworthiness directive (AD) that applies to certain Boeing Model 737- 100, -200, -200C, -300, -400, and -500 series airplanes. That AD supersedes AD 99-05-15, amendment 39-11063, to require a one-time inspection of the attachment nuts at each end attachment of the elevator tab push rods to measure run-on torque values, and corrective actions, if necessary. That AD also requires replacement of all existing bolts and attachment nuts at the forward and aft end attachment of each elevator tab push rod with new bolts and self- locking castellated nuts with cotter pins. This document corrects an inadvertent error regarding the compliance time for certain requirements of that AD. This correction is necessary to provide an adequate compliance time for the replacement of certain parts.
To prevent detachment of an elevator tab push rod due to a detached nut at either end attachment of a push rod, which could result in excessive high-frequency airframe vibration during flight; consequent structural damage to the elevator tab, elevator, and horizontal stabilizer; and reduced controllability of the airplane; accomplish the following:
(a) Within 90 days after March 23, 1999 (the effective date of AD 99-05-15, amendment 39-11063): Perform a one-time inspection of all attachment nuts at each end of each elevator tab push rod to measure the run-on torque values of the nuts, in accordance with Boeing Alert Service Bulletin 737-27A1205, dated August 28, 1997.
(1) If the run-on torque value of any end attachment nut is within the limits specified in the alert service bulletin, prior to further flight, ensure that the final seating torque of the attachment nuts is within the torque values specified in the alert service bulletin.
(2) If the run-on torque value of any end attachment nut is outside the limits specified in the alert service bulletin, prior to further flight, replace all existing bolts and attachment nuts at each end of each elevator tab push rod with new bolts and self-locking castellated nuts that have cotter pins installed as a secondary locking feature, in accordance with Boeing Service Letter 737-SL-27-118-D, dated December 17, 1999, and ensure that the final seating torque of the nuts is within the torque values specified in the service letter.
Note 2: Accomplishment of the inspection and ensuring adequate final seating torque values prior to the effective date of this AD in accordance with Boeing All-Base Telex M-7272-97-0897, dated February 13, 1997, are considered acceptable for compliance with the actions specified in paragraphs (a) and (a)(1) of this AD for only the forward attachment nuts.
(b) Within 24 months or 4,000 flight cycles after the effective date of this AD, whichever occurs first: Replace all existing bolts and attachment nuts at the forward and aft end attachment of each elevator tab push rod with new bolts and self-locking castellated nuts that have cotter pins installed as a secondary locking feature, in accordance with Boeing Service Letter 737-SL-27-118-D, dated December 17, 1999.
Note 3: Replacements accomplished prior to the effective date of this AD in accordance with Boeing Service Letter 737-SL-27-118-A, dated November 14, 1997; 737-SL-27-118-B, dated April 14, 1999; or 737-SL-27-118-C, dated May 19, 1999; are considered acceptable for compliance with paragraphs (a)(2) and (b) of this AD.
(c)(1) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.
(2) Alternative methods of compliance, approved previously in accordance with AD 99-05-15, amendment 39-11063, are considered to be approved as alternative methods of compliance with paragraph (a) of this AD only.
Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
