AD 79-26-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 737-200 Series | BOEING Model 737-200 Airplanes |
Unsafe Condition
GPWS flap position switches sensing less than 30 degrees as landing flaps could fail to provide proper warning during landing configurations, increasing the risk of controlled flight into terrain.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replace the ground proximity warning system (GPWS) flap position switch to sense flaps 30 and 40 degrees as landing positions and install a flap override switch for landings requiring flap positions of 25 degrees or less.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within the next 1,200 hours time-in-service or six (6) months, whichever comes first, after the effective date of this AD
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Model 737-200 (advanced) airplanes with GPWS flap position switches sensing less than 30 degrees as landing flaps, certificated in all categories
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
GPWS Flap Position Switches
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_79-26-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 79-26-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: BOEING Model 737-200 Airplanes Subject: GPWS Flap Position Switches Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/31/1979 Make: The Boeing Company Model: 737-200 Series Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 79-26-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3638 AD NUMBER: 79-26-02 SUBJECT HEADING: BOEING Model 737-200 Airplanes ACTION: SUMMARY: DATES: Effective December 31, 1979. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 79-26-02 BOEING: Amendment 39-3638. Applies to all Model 737-200 (advanced) airplanes with GPWS flap position switches sensing less than 30 degrees as landing flaps, certificated in all categories. Compliance required as indicated. Accomplish the following: Within the next 1,200 hours time-in-service or six (6) months, whichever comes first, after the effective date of this AD, change the ground proximity warning system flap position switch to sense flaps 30 degrees and 40 degrees as the landing flap positions, and provide a flap override switch for landings that must proceed with flap position of 25 degrees or less. This modification may be accomplished in accordance with modifications approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington 98108. This amendment becomes effective December 31, 1979. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_79-26-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 79-26-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: BOEING Model 737-200 Airplanes Subject: GPWS Flap Position Switches Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/31/1979 Make: The Boeing Company Model: 737-200 Series Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 79-26-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3638 AD NUMBER: 79-26-02 SUBJECT HEADING: BOEING Model 737-200 Airplanes ACTION: SUMMARY: DATES: Effective December 31, 1979. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 79-26-02 BOEING: Amendment 39-3638. Applies to all Model 737-200 (advanced) airplanes with GPWS flap position switches sensing less than 30 degrees as landing flaps, certificated in all categories. Compliance required as indicated. Accomplish the following: Within the next 1,200 hours time-in-service or six (6) months, whichever comes first, after the effective date of this AD, change the ground proximity warning system flap position switch to sense flaps 30 degrees and 40 degrees as the landing flap positions, and provide a flap override switch for landings that must proceed with flap position of 25 degrees or less. This modification may be accomplished in accordance with modifications approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington 98108. This amendment becomes effective December 31, 1979. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2025-02-02 Recurring
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: cracks in the frame inner chord and web at station (STA) 727 between S-11L and S-13L, which could result in the inability of a principal structural element to sustain limit load, and adversely affe...
2023-13-12 Recurring
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: premature aging of certain passenger chemical oxygen generators, which could fail to deliver oxygen during an emergency, possibly resulting in injury to the airplane occupants.
2023-12-13
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: Radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations in the 5G C-Band. This interference can cause other airp...
2023-10-02
final ruleAirworthiness Directives; Transport and Commuter Category Airplanes
Unsafe Condition: Radio altimeter anomalies that are undetected by the automation or pilot, particularly close to the ground (e.g., landing flare), could lead to loss of continued safe flight and landing. Additional...