AD 93-23-06
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Canada Corp. | PT6A-50 | PRATT & WHITNEY CANADA Model PT6A-50 Series Engines |
Unsafe Condition
Engine failure debris causing aircraft damage due to metal debris in the engine chip detector and open circuit wiring in the airframe chip detector flag system.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the airframe chip detector flag system daily starting one calendar day after the effective date. Within 50 hours time in service, remove and inspect the engine chip detector for metal debris, replace part number 3040019 with 3026609, inspect circuit wiring, perform a one-time grounding check, inspect main oil filter, and replace PT shroud by December 31, 1994.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within one calendar day after the effective date, within 50 hours time in service, thereafter at intervals not to exceed 100 hours time in service, and PT shroud replacement by December 31, 1994.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Pratt & Whitney Canada PT6A-50 series engines installed on but not limited to DeHavilland DHC-7 turboprop aircraft.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Airframe Chip Detector Flag System
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_93-23-06.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 93-23-06 Document Type: AD Final Rules Docket Number: 91-ANE-49 Subject Heading: PRATT & WHITNEY CANADA Model PT6A-50 Series Engines Subject: Airframe Chip Detector Flag System Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 01/26/1994 Make: Pratt & Whitney Canada Corp. Model: PT6A-50 Product Type: Engine Product Subtype: Affected AD: Superseded AD: 88-24-02 Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 93-23-06 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 91-ANE-49 AMENDMENT: 39-8740 AD NUMBER: 93-23-06 SUBJECT HEADING: PRATT & WHITNEY CANADA Model PT6A-50 Series Engines ACTION: SUMMARY: DATES: Effective January 26, 1994. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 93-23-06 PRATT & WHITNEY CANADA: Amendment 39-8740. Docket No. 91-ANE-49. Supersedes priority letter AD 88-24-02. Applicability: Pratt & Whitney Canada (PWC) PT6A-50 series turboprop engines installed on but not limited to DeHavilland DHC-7 turboprop aircraft. Compliance: Required as indicated, unless accomplished previously. To prevent aircraft damage from engine failure debris, accomplish the following: (a) Within one calendar day after the effective date of this AD, inspect the airframe chip detector flag system, and thereafter reinspect each day of operation, in accordance with DeHavilland Canada (DHC) Dash 7 Maintenance Manual, Section 71-05-00, dated July 15, 1977. If the chip detector flag is actuated, accomplish paragraphs (b)(1), (b)(2), and (b)(4) of this AD, prior to further flight. (b) Within the next 50 hours time in service (TIS) after the effective date of this AD, accomplish the following: (1) Remove and visually inspect the engine chip detector for metal debris, in accordance with PWC PT6A-50 Maintenance Manual, Section 79-35-02, dated January 15, 1991, and based on the inspection results, accomplish the applicable procedures specified in Section 79-35-02, dated January 15, 1991. (2) Remove from service engine chip detector Part Number (P/N) 3040019, if installed, and replace with engine chip detector P/N 3026609. (3) Inspect the circuit wiring of the installed or replacement engine chip detector, P/N 3026609, in accordance with PWC PT6A-50 Maintenance Manual, Section 79-35-02, dated January 15, 1991. Remove from service, prior to further flight, engine chip detectors found with an open circuit and replace with serviceable engine chip detectors. (4) Perform a one-time inspection check of the airframe chip detector flag system by grounding the wiring pins in the connector to the chip detector, in accordance with PWC Alert Service Information Letter (SIL) No. 4019, dated October 20, 1988. If the chip detector flag is not actuated in the nacelle, correct defects and repeat this inspection check until the chip detector flag actuation is confirmed (reference DeHavilland Canada Dash 7 Maintenance Manual, Section 71-05-00, dated July 15, 1977). (5) Inspect the main oil filter for contamination, and based on the inspection results, accomplish the applicable procedures specified in PWC PT6A-50 Maintenance Manual, Section 79-25-04, dated January 15, 1991. (c) Thereafter, inspect the main oil filter at intervals not to exceed 100 hours TIS since the last inspection in accordance with the requirements of paragraph (b)(5) of this AD. If visible metallic debris is evident, accomplish paragraph (b)(1) of this AD prior to further flight. (d) Remove, inspect, and reinstall the engine chip detector of non-installed engines, in accordance with paragraphs (b)(1), (b)(2), and (b)(3) above, prior to entering service. NOTE: Paragraphs (a) through (d) of this AD repeat the compliance requirements of paragraphs (a) through (d) of priority letter AD 88-24-02. (e) Remove from service power turbine (PT) shroud, Part Number (P/N) 3023797, and replace with PT shroud, P/N 3112919-01, in accordance with PWC Service Bulletin (SB) No. 4143R2, dated December 6, 1991, on or before December 31, 1994. PWC SB 4143, dated May 31, 1989, and PWC SB 4143, Revision 1, dated February 12, 1990, are acceptable alternate means of compliance to this AD. Installation of PT shroud, P/N 3112919-01, constitutes terminating action to the inspection requirements of this AD. (f) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office. (g) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the aircraft to a location where the requirements of this AD can be accomplished. (h) The modification shall be done in accordance with the following documents: Document No. Page No. Issue Date DHC-7 Maintenance Manual, Section 71-05-00 1-3 Original Jul 15, 1977 Total pages: 3 PWC PT6A-50 1 Original Apr 5, 1976 Maintenance Manual, 2 Original Mar 1, 1977 Section 79-35-02 201 Original Jan 26, 1983 202 Original Apr 5, 1976 203 Original Jan 15, 1991 204 Original Jan 26, 1983 Total pages: 6 PWC Alert SIL No. 4019 1-2 Original Oct 20, 1988 Total pages: 2 PWC PT6A-50 202 A&B Original Jan 26, 1983 Maintenance Manual, 204, & Section 79-25-04 209 203 Original Apr 5, 1976 205-6 Original Jan 15, 1991 207-8, Original Apr 2, 1987 & 210 Total pages: 10 PWC (SB) No. 4143R2 1-2 Revision 2 Dec 6, 1991 Total pages: 2 This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Pratt & Whitney Canada, Technical Publications Department, 1000 Marie Victorin, Longueuil, Quebec J4G 1A1. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (i) This amendment becomes effective on January 26, 1994. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_93-23-06.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 93-23-06 Document Type: AD Final Rules Docket Number: 91-ANE-49 Subject Heading: PRATT & WHITNEY CANADA Model PT6A-50 Series Engines Subject: Airframe Chip Detector Flag System Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 01/26/1994 Make: Pratt & Whitney Canada Corp. Model: PT6A-50 Product Type: Engine Product Subtype: Affected AD: Superseded AD: 88-24-02 Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 93-23-06 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 91-ANE-49 AMENDMENT: 39-8740 AD NUMBER: 93-23-06 SUBJECT HEADING: PRATT & WHITNEY CANADA Model PT6A-50 Series Engines ACTION: SUMMARY: DATES: Effective January 26, 1994. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 93-23-06 PRATT & WHITNEY CANADA: Amendment 39-8740. Docket No. 91-ANE-49. Supersedes priority letter AD 88-24-02. Applicability: Pratt & Whitney Canada (PWC) PT6A-50 series turboprop engines installed on but not limited to DeHavilland DHC-7 turboprop aircraft. Compliance: Required as indicated, unless accomplished previously. To prevent aircraft damage from engine failure debris, accomplish the following: (a) Within one calendar day after the effective date of this AD, inspect the airframe chip detector flag system, and thereafter reinspect each day of operation, in accordance with DeHavilland Canada (DHC) Dash 7 Maintenance Manual, Section 71-05-00, dated July 15, 1977. If the chip detector flag is actuated, accomplish paragraphs (b)(1), (b)(2), and (b)(4) of this AD, prior to further flight. (b) Within the next 50 hours time in service (TIS) after the effective date of this AD, accomplish the following: (1) Remove and visually inspect the engine chip detector for metal debris, in accordance with PWC PT6A-50 Maintenance Manual, Section 79-35-02, dated January 15, 1991, and based on the inspection results, accomplish the applicable procedures specified in Section 79-35-02, dated January 15, 1991. (2) Remove from service engine chip detector Part Number (P/N) 3040019, if installed, and replace with engine chip detector P/N 3026609. (3) Inspect the circuit wiring of the installed or replacement engine chip detector, P/N 3026609, in accordance with PWC PT6A-50 Maintenance Manual, Section 79-35-02, dated January 15, 1991. Remove from service, prior to further flight, engine chip detectors found with an open circuit and replace with serviceable engine chip detectors. (4) Perform a one-time inspection check of the airframe chip detector flag system by grounding the wiring pins in the connector to the chip detector, in accordance with PWC Alert Service Information Letter (SIL) No. 4019, dated October 20, 1988. If the chip detector flag is not actuated in the nacelle, correct defects and repeat this inspection check until the chip detector flag actuation is confirmed (reference DeHavilland Canada Dash 7 Maintenance Manual, Section 71-05-00, dated July 15, 1977). (5) Inspect the main oil filter for contamination, and based on the inspection results, accomplish the applicable procedures specified in PWC PT6A-50 Maintenance Manual, Section 79-25-04, dated January 15, 1991. (c) Thereafter, inspect the main oil filter at intervals not to exceed 100 hours TIS since the last inspection in accordance with the requirements of paragraph (b)(5) of this AD. If visible metallic debris is evident, accomplish paragraph (b)(1) of this AD prior to further flight. (d) Remove, inspect, and reinstall the engine chip detector of non-installed engines, in accordance with paragraphs (b)(1), (b)(2), and (b)(3) above, prior to entering service. NOTE: Paragraphs (a) through (d) of this AD repeat the compliance requirements of paragraphs (a) through (d) of priority letter AD 88-24-02. (e) Remove from service power turbine (PT) shroud, Part Number (P/N) 3023797, and replace with PT shroud, P/N 3112919-01, in accordance with PWC Service Bulletin (SB) No. 4143R2, dated December 6, 1991, on or before December 31, 1994. PWC SB 4143, dated May 31, 1989, and PWC SB 4143, Revision 1, dated February 12, 1990, are acceptable alternate means of compliance to this AD. Installation of PT shroud, P/N 3112919-01, constitutes terminating action to the inspection requirements of this AD. (f) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office. (g) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the aircraft to a location where the requirements of this AD can be accomplished. (h) The modification shall be done in accordance with the following documents: Document No. Page No. Issue Date DHC-7 Maintenance Manual, Section 71-05-00 1-3 Original Jul 15, 1977 Total pages: 3 PWC PT6A-50 1 Original Apr 5, 1976 Maintenance Manual, 2 Original Mar 1, 1977 Section 79-35-02 201 Original Jan 26, 1983 202 Original Apr 5, 1976 203 Original Jan 15, 1991 204 Original Jan 26, 1983 Total pages: 6 PWC Alert SIL No. 4019 1-2 Original Oct 20, 1988 Total pages: 2 PWC PT6A-50 202 A&B Original Jan 26, 1983 Maintenance Manual, 204, & Section 79-25-04 209 203 Original Apr 5, 1976 205-6 Original Jan 15, 1991 207-8, Original Apr 2, 1987 & 210 Total pages: 10 PWC (SB) No. 4143R2 1-2 Revision 2 Dec 6, 1991 Total pages: 2 This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Pratt & Whitney Canada, Technical Publications Department, 1000 Marie Victorin, Longueuil, Quebec J4G 1A1. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (i) This amendment becomes effective on January 26, 1994. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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