Airworthiness Directive · Amendment 39-21332 · Auto flight
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 737-8 and 737-9 airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 737-31-1860, Revision 1, dated July 2, 2020.
The FAA is superseding Airworthiness Directive (AD) 2018-23- 51, which applied to all The Boeing Company Model 737-8 and 737-9 (737 MAX) airplanes. AD 2018-23-51 required revising certificate limitations and operating procedures of the Airplane Flight Manual (AFM) to provide the flightcrew with runaway horizontal stabilizer trim procedures to follow under certain conditions. This AD requires installing new flight control computer (FCC) software, revising the existing AFM to incorporate new and revised flightcrew procedures, installing new MAX display system (MDS) software, changing the horizontal stabilizer trim wire routing installations, completing an angle of attack (AOA) sensor system test, and performing an operational readiness flight. This AD also applies to a narrower set of airplanes than the superseded AD, and only allows operation (dispatch) of an airplane with certain inoperative systems if specific, more restrictive, provisions are incorporated into the operator's existing FAA-approved minimum equipment list (MEL). This AD was prompted by the potential for a single erroneously high AOA sensor input received by the flight control system to result in repeated airplane nose-down trim of the horizontal stabilizer. The FAA is issuing this AD to address the unsafe condition on these products.
Before further flight, install FCC OPS software version P12.1.2, part number (P/N) 2274-COL-AC2-26, or later-approved software versions, on FCC A and FCC B, and do a software installation verification. During the installation verification, if the approved software part number is not shown as being installed on FCC A and FCC B, before further flight, do corrective actions until the approved software part number is installed on FCC A and FCC B. Later-approved software versions are only those Boeing software versions that are approved as a replacement for the applicable software, and are approved as part of the type design by the FAA after the effective date of this AD. Accomplishment of all applicable actions identified as “RC” (required for compliance) in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-22A1342 RB, dated November 17, 2020, is acceptable for compliance with the requirements of this paragraph.
Note 1 to paragraph (g): Guidance for doing the installation and installation verification of the FCC OPS software can be found in Boeing 737-7/8/8200/9/10 Aircraft Maintenance Manual (AMM), Section 22-11-33.
Note 2 to paragraph (g): Guidance for accomplishing the actions required by paragraph (g) can also be found in Boeing Alert Service Bulletin 737-22A1342, dated November 17, 2020, which is referred to in Boeing Alert Requirements Bulletin 737-22A1342 RB, dated November 17, 2020.
Before further flight, revise the existing AFM to include the changes specified in paragraphs (h)(1) through (10) of this AD. Revising the existing AFM to include the changes specified in paragraphs (h)(2) through (10) of this AD may be done by inserting a copy of figure 1 to paragraph (h)(2) through figure 9 to paragraph (h)(10) into the existing AFM.
(1) In the Certificate Limitations and Operating Procedures chapters, remove the information identified as “Required by AD 2018-23-51.”
(2) In the Operating Procedures chapter, revise the General paragraph to include the information in figure 1 to paragraph (h)(2) of this AD.
(3) In the Operating Procedures chapter, replace the existing Airspeed Unreliable paragraph with the information in figure 2 to paragraph (h)(3) of this AD.
(4) In the Operating Procedures chapter, replace the existing Runaway Stabilizer paragraph with the information in figure 3 to paragraph (h)(4) of this AD.
(5) In the Operating Procedures chapter, replace the existing Stabilizer Trim Inoperative paragraph with the information in figure 4 to paragraph (h)(5) of this AD.
(6) In the Operating Procedures chapter, add the information in figure 5 to paragraph (h)(6) of this AD.
(7) In the Operating Procedures chapter, add the information in figure 6 to paragraph (h)(7) of this AD.
(8) In the Operating Procedures chapter, add the information in figure 7 to paragraph (h)(8) of this AD.
(9) In the Operating Procedures chapter, add the information in figure 8 to paragraph (h)(9) of this AD.
(10) In the Operating Procedures chapter, add the information in figure 9 to paragraph (h)(10) of this AD.
In the event that the airplane functions associated with the flight control system as modified by this AD are inoperative, an airplane may be operated (dispatched) only if the provisions specified in figure 10 to paragraph (i) of this AD are incorporated into the operator's existing FAA-approved MEL.
Note 3 to paragraph (i): The MEL provisions specified in figure 10 to paragraph (i) of this AD correspond to Master Minimum Equipment List (MMEL) items 22-10-01B, 22-10-02, 22-10-03, 22-11-01, 22-11-02, 22-11-05-02B, 22-11-06-02B, 22-11-08-01A, 22-11-08-01B, 22-11-10A, 22-11-10B, and 27-41-01, in the existing FAA-approved Boeing 737 MAX B-737-8/-9 MMEL, Revision 2, dated April 10, 2020, which can be found on the Flight Standards Information Management System (FSIMS) website, https://fsims.faa.gov/PICResults.aspx?mode=Publication&doctype=MMELByModel.
Before further flight, do all applicable actions identified as “RC” in, and in accordance with, the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-31-1860, Revision 1, dated July 2, 2020.
Before further flight, do all applicable actions identified as “RC” in, and in accordance with, the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-27-1318, Revision 2, dated November 10, 2020.
Before further flight, do all applicable actions identified as “RC” for the “Angle of Attack (AOA) Sensor System Test” specified in, and in accordance with, the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-00-1028, dated July 20, 2020.
(1) After accomplishment of all applicable required actions in paragraphs (g) through (l) of this AD, do all applicable actions identified as “RC” for the “Operational Readiness Flight” specified in, and in accordance with, the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-00-1028, dated July 20, 2020. The “Operational Readiness Flight” required by this paragraph must be accomplished before any other flight. A special flight permit is not required to accomplish the “Operational Readiness Flight” required by this paragraph.
(2) After the “Operational Readiness Flight” and before further flight, any mechanical irregularities that occurred during the “Operational Readiness Flight” must be resolved following the operator's FAA-approved maintenance or inspection program, as applicable.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
