Airworthiness Directive · Amendment 39-11663 · Boeing Model 737-600, -700, and 800 Series Airplanes
Boeing Model 737-600, -700, and 800 Series Airplanes
Model 737-600, -700, and -800 series airplanes, line numbers 1 through 477 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) 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 amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-600, -700, and 800 series airplanes. This action requires a one-time inspection to detect loose nuts installed on the bolts at each end of the input rods connected to each elevator power control unit (PCU), and corrective action, if necessary. This amendment is prompted by reports of loose nuts on the bolts that connect the lower input crank arm and the vernier adjustment input rod of the elevator PCU. The actions specified in this AD are intended to detect and correct loose nuts on the bolts of the input crank arms of the elevator PCU, which could result in the loss of pivot bolts on the PCU and consequent loss of control of the airplane during takeoff and landing.
To prevent loss of control of the airplane during takeoff and landing due to loose nuts on the bolts of the input crank arms of the elevator power control unit (PCU), and consequent loss of pivot bolts, accomplish the following:
Note 2: For the purposes of this AD, a general visual inspection is defined as:“A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
(a) Within 30 days after the effective date of this AD, perform a one-time general visual inspection to determine if the nuts installed on the bolts at each end of the input rods connected to each elevator PCU are installed correctly, in accordance with Boeing Telegraphic Service Letter 737-SL-27-150, dated February 14, 2000.
(1) If all bolts are protruding through the nuts, no further action is required by this AD.
(2) If any bolt does not protrude through the nut, prior to further flight, tighten the nut in accordance with the telegraphic service letter.
(b) Within 10 days after accomplishing the inspection required by this AD; or within 10 days after the effective date of this AD if the inspection was accomplished prior to the effective date of this AD: Submit a report of any findings of loose nuts to the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (425) 227-1181. The report must include the operator's name, the date the inspection was accomplished, the airplane line number, and the number of loose nuts found on that airplane. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.
