Airworthiness Directive · Amendment 39-17224 · Auto flight
The Boeing Company Airplanes
Superseded. A later AD replaced this one: AD 2021-18-17. Comply with the one in force.
This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category; delivered with the Rockwell Collins Enhanced Digital Flight Control System (EDFCS), as identified in the variable number table in Section 1.A.1., Effectivity, of Boeing Alert Service Bulletin 737-22A1211, dated April 13, 2010. This AD is applicable to all airplanes listed in the variable number table, and is not defined by the “Group 1” description in Section 1.A. of Boeing Alert Service Bulletin 737-22A1211, dated April 13, 2010.
We are superseding an existing airworthiness directive (AD) for certain The Boeing Company Model 737-600, -700, -700C, -800, and - 900 series airplanes. That AD currently requires installing and testing an updated version of the operational program software (OPS) of the flight control computers (FCCs). This new AD requires an inspection for part numbers of the operational program software of the flight control computers, and corrective actions if necessary. This AD was prompted by reports of undetected erroneous output from a single radio altimeter channel, which resulted in premature autothrottle retard during approach. We are issuing this AD to detect and correct an unsafe condition associated with erroneous output from a radio altimeter channel, which could result in premature autothrottle landing flare retard and the loss of automatic speed control, and consequent loss of control of the airplane.
This paragraph restates the requirements of paragraph (f) of AD 2005-07-20, Amendment 39-14045 (70 FR 17603, April 7, 2005). For airplanes identified in Boeing Alert Service Bulletin 737-22A1164, dated May 20, 2004: Within 12 months after May 12, 2005 (the effective date of AD 2005-07-20), install and test an updated version of the operational program software (OPS) of the EDFCS flight control computers (FCCs), in accordance with Boeing Alert Service Bulletin 737-22A1164, dated May 20, 2004. Installing software as required by paragraph (h)(1)(i) or (h)(1)(ii) of this AD, or verifying that the software is installed as specified by paragraph (h)(2) of this AD, or doing the actions specified in paragraph (i) of this AD, terminates the requirements of this paragraph.
Within 3 months after the effective date of this AD: Inspect to determine the part number of the OPS of the FCCs, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-22A1211, dated April 13, 2010. Installing software as required by paragraph (h)(1)(i) or (h)(1)(ii) of this AD, or verifying that the software is installed as specified by paragraph (h)(2) of this AD, terminates the requirements of paragraph (g) of this AD. Doing the actions specified in paragraph (i) of this AD, terminates the requirements of this paragraph.
(1) For any OPS having a part number identified in table 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-22A1211, dated April 13, 2010: Before further flight, do the actions specified in paragraph (h)(1)(i) or (h)(1)(ii), as applicable.
(i) Install software identified in table 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-22A1211, dated April 13, 2010, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-22A1211, dated April 13, 2010.
(ii) Install software identified in table 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-22A1224, dated May 18, 2012, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-22A1224, dated May 18, 2012.
(2) For any OPS having a part number identified in table 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-22A1211, dated April 13, 2010; or in table 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-22A1224, dated May 18, 2012: No further action is required by this paragraph.
Installing a version of the FCC OPS approved after May 18, 2012 (the issue date of Boeing Alert Service Bulletin 737-22A1224) terminates the requirements of paragraphs (g) and (h) of this AD, provided that the conditions specified in paragraphs (i)(1) and (i)(2) of this AD are met.
(1) The version of the FCC OPS must be approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; the Manager, Boeing Aviation Safety Oversight Office (BASOO), FAA; or the Boeing Commercial Airplanes Organization Designation Authorization (ODA).
(2) The installation must be done in accordance with a method approved by the Manager, Seattle ACO, FAA; the Manager, BASOO, FAA; or the Boeing Commercial Airplanes ODA.
