# AD 82-26-01: Dual Channel Autopilot With M & L Unit - Type: Airworthiness directive - Status: Current - Products: Boeing 747-100 Series, 747-100B Series, 747-100B SUD Series, 747-200B Series, 747-200C Series, 747-200F Series, 747-300 Series, 747-400 Series, 747-400D Series, 747-400F Series, 747SP Series and 747SR Series - Effective: January 17, 1983 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-4514 - Registered aircraft: 63 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F7184D9DAE3447FD862568A8005D13D0.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/82-26-01 ## The airworthiness directive 82-26-01 BOEING: Amendment 39-4514. Applies to all Boeing Model 747 Series airplanes equipped with a dual channel autopilot with a Monitor and Logic (M & L) Unit, Boeing Part Number 60B00013-452, -453, -454, and on, listed in Boeing Service Bulletin 747-22-2130, Fail- Passive Autopilot Stabilizer Trim Bias and Automatic Disconnect Modification. Compliance required as indicated. To prevent no-flare automatic landings with excessive sink rates, accomplish the requirements of paragraph A and either paragraph B or C below within 180 days after the effective date of this AD: A. Incorporate the following limitations as appropriate in "Section 1 - Certification Limitations" of the Airplane Flight Manual: 1. On airplanes equipped with an operating Autoland Bias Control System, incorporate the following limitation: "Autopilot - Autopilot use below 50 feet AGL is prohibited except when Boeing Service Bulletin 747-22-2127 FAIL PASSIVE AUTOPILOT FLARE COMMAND WIRING MODIFICATION or FAA approved production equivalent is installed and one of the following conditions is met: (a) At flaps 25 - the ground speed on final approach is less than 187 kts. (b) At flaps 30 - the ground speed on final approach is less than 173 kts." 2. On all other airplanes incorporate the following limitation: "Autopilot - Autopilot use below 50 feet AGL is prohibited except when Boeing Service Bulletin 747-22- 2127 FAIL PASSIVE AUTOPILOT FLARE COMMAND WIRING MODIFICATION or FAA approved production equivalent is installed and one of the following conditions is met: (a) At flaps 25 - the ground speed on final approach is less than 180 kts. (b) At flaps 30 - the ground speed on final approach is less than 163 kts." B. Install a placard on the autopilot flight director mode select panel which reads: "DO NOT USE AUTOPILOT BELOW 50 FT. AGL." C. Accomplish Boeing Service Bulletin 747-22-2127, FAIL PASSIVE AUTOPILOT FLARE COMMAND WIRING MODIFICATION or FAA approved production equivalent. Install a placard on the autopilot flight director mode select panel which reads: "DO NOT USE AUTOPILOT BELOW 50 FT AGL EXCEPT PER FLIGHT MANUAL LIMITATIONS." D. Accomplishment of Boeing Service Bulletin 747-22-2130 provides terminating action and allows removal of the placard and flight manual limitations required by paragraphs A, B, and C above. E. Alternate means of compliance with this AD which provide an equivalent level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. F. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). This amendment becomes effective January 17, 1983. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A20WE](https://openairdocs.org/tcds/A20WE): The Boeing Company; names 12 of 14 models: 747-100B Series, 747SP Series, 747-400D Series, 747-400F Series, 747-200B Series, 747-200F Series, 747-300 Series, 747-200C Series… ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 63 (63 by airframe model, 0 by engine model) - Makers: Boeing 63 Models with the most aircraft: - [Boeing 747-446](https://openairdocs.org/model/boeing-747-446): 10 aircraft (airframe model) - [Boeing 747-422](https://openairdocs.org/model/boeing-747-422): 8 aircraft (airframe model) - [Boeing 747-412](https://openairdocs.org/model/boeing-747-412): 5 aircraft (airframe model) - [Boeing 747-400F](https://openairdocs.org/model/boeing-747-400f): 4 aircraft (airframe model) - [Boeing 747-409](https://openairdocs.org/model/boeing-747-409): 4 aircraft (airframe model) - [Boeing 747-481F](https://openairdocs.org/model/boeing-747-481f): 3 aircraft (airframe model) - [Boeing 747-409F](https://openairdocs.org/model/boeing-747-409f): 3 aircraft (airframe model) - [Boeing 747-481](https://openairdocs.org/model/boeing-747-481): 3 aircraft (airframe model) - [Boeing 747-428F](https://openairdocs.org/model/boeing-747-428f): 3 aircraft (airframe model) - [Boeing 747-123](https://openairdocs.org/model/boeing-747-123): 2 aircraft (airframe model) - [Boeing 747-251F](https://openairdocs.org/model/boeing-747-251f): 2 aircraft (airframe model) - [Boeing 747-443](https://openairdocs.org/model/boeing-747-443): 2 aircraft (airframe model) - [Boeing 747-438](https://openairdocs.org/model/boeing-747-438): 2 aircraft (airframe model) - [Boeing 747-428](https://openairdocs.org/model/boeing-747-428): 2 aircraft (airframe model) - [Boeing 747-257B](https://openairdocs.org/model/boeing-747-257b): 1 aircraft (airframe model) - [Boeing 747-283B](https://openairdocs.org/model/boeing-747-283b): 1 aircraft (airframe model) - [Boeing 747-121](https://openairdocs.org/model/boeing-747-121): 1 aircraft (airframe model) - [Boeing 747-131](https://openairdocs.org/model/boeing-747-131): 1 aircraft (airframe model) - [Boeing 747-128](https://openairdocs.org/model/boeing-747-128): 1 aircraft (airframe model) - [Boeing 747-273C](https://openairdocs.org/model/boeing-747-273c): 1 aircraft (airframe model) All 24 models: https://openairdocs.org/ad/82-26-01/models.md Every aircraft: https://openairdocs.org/ad/82-26-01/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.