AD 47-31-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sierra Hotel Aero, Inc. | Navion (Army L-17A) | Airworthiness Directives; Navion Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler Model 2250 Fuel Strainers |
Unsafe Condition
Loss of fuel pressure due to air leakage into the fuel system through the CCA-1550-1/8 drain cock on the Koehler Model 2250 fuel strainer.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove the CCA-1550-1/8 drain cock and install the Whittaker Model 7600-1/8 drain cock.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
not later than November 1, 1947
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Navion Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler Model 2250 Fuel Strainers.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Fuel Drain Cock
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_47-31-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-31-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Navion Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler...Show more Subject: Fuel Drain Cock Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Sierra Hotel Aero, Inc. Model: Navion (Army L-17A) Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 47-31-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-31-03 SUBJECT HEADING: Airworthiness Directives; Navion Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler Model 2250 Fuel Strainers ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-31-03 NAVION: (Was mandatory Note 12 of AD-782-3.) Applies to Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler Model 2250 Fuel Strainers. To be accomplished not later than November 1, 1947. To preclude the possibility of loss of fuel pressure due to air leakage into the fuel system through the CCA-1550-1/8 drain cock on the Koehler Model 2250 fuel strainer, remove this draincock and install Whittaker Model 7600-1/8 drain cock. (NAA Field Service Bulletin No. 32 dated May 1, 1947, covers this rework.) FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_47-31-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-31-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Navion Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler...Show more Subject: Fuel Drain Cock Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Sierra Hotel Aero, Inc. Model: Navion (Army L-17A) Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 47-31-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-31-03 SUBJECT HEADING: Airworthiness Directives; Navion Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler Model 2250 Fuel Strainers ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-31-03 NAVION: (Was mandatory Note 12 of AD-782-3.) Applies to Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler Model 2250 Fuel Strainers. To be accomplished not later than November 1, 1947. To preclude the possibility of loss of fuel pressure due to air leakage into the fuel system through the CCA-1550-1/8 drain cock on the Koehler Model 2250 fuel strainer, remove this draincock and install Whittaker Model 7600-1/8 drain cock. (NAA Field Service Bulletin No. 32 dated May 1, 1947, covers this rework.) 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
2008-05-14 Recurring
final ruleAirworthiness Directives; Sierra Hotel Aero, Inc. Models Navion (L-17A), Navion A (L-17B), (L-17C), Navion B, Navion D, Navion E, Navion F, Navion G, and Navion H Airplanes
Unsafe Condition: Leaking or improperly operating fuel selector valves may disrupt fuel flow to the engine, leading to engine power loss.
68-20-06
final ruleAirworthiness Directives; Navion Models Navion through Navion H Airplanes
Unsafe Condition: Failure of the Rudder Horn, P/N 145-24401, due to horizontal cracks or corrosion in the edge, which may appear as delaminations or swelling under the paint.
62-03-03
final ruleAirworthiness Directives; Navion Models Navion, Navion A, Navion B, Navion D, Navion E, Navion F, and Navion G Aircraft
Unsafe Condition: The landing gear selector valve end fitting P/N 145-58145-3 (heat treated and non-heat treated) has a service history of failure during attempts to extend the gear.
49-05-03
final ruleAirworthiness Directives; Navion Airplanes Equipped With Continental Model E185-3 Engines Having Serial Numbers 4289-D to 5110-D Inclusive, and Engines Which Have Been Equipped at Overhaul With Tri-Metal Front Main Bearing Inserts and Bronze Thrust Washers in Accordance With Continental Bulletin No. M48-7.
Unsafe Condition: Unsatisfactory service experience with Continental E185-3 engines equipped with No. 530497 Tri-Metal front main bearing inserts and thrust washers/pins (Nos. 530494, 530495, 530544 and 530545 dowel...
