AD 72-20-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Textron Aviation Inc. | 65-90 | Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes |
| aircraft | Textron Aviation Inc. | 65-A90 | Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes |
| aircraft | Textron Aviation Inc. | 99 | Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes |
| aircraft | Textron Aviation Inc. | 99A | Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes |
| aircraft | Textron Aviation Inc. | A99A | Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes |
| aircraft | Textron Aviation Inc. | B90 | Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes |
| aircraft | Textron Aviation Inc. | B99 | Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes |
Unsafe Condition
Heater overheat melts the windshield defroster ducting, damages wiring beneath the instrument panel, and fills the cabin with smoke.
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Required Actions
Prohibit heater operation if the ventilation blower is not functioning. Prior to each flight, determine the ventilation blower is operating. Within 25 hours' time in service after the effective date, replace vent blower and combustion differential switches with Beech P/N 90-380010-1 differential pressure switches per Service Instructions No. 0500-412 or later. Inspect heater fuse for proper standard value and install correct fuse if needed before further flight.
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Compliance Time
Effective immediately for prohibitions and checks. Within 25 hours' time in service after September 27, 1972, for switch replacement and fuse inspection.
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Affected Aircraft
BEECH Models 65-90, 65-A90, B90 (Serial Numbers LJ-1 thru LJ-501) and Models 99, 99A, A99A, B99 (Serial Numbers U-1 thru U-151).
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Heater Overheat
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_72-20-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 72-20-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes Subject: Heater Overheat Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/27/1972 Make: Textron Aviation Inc. Model: 65-90 | 65-A90 | 99 | 99A | A99A | B90 | B99 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: 72-20-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1524 AD NUMBER: 72-20-03 SUBJECT HEADING: Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes ACTION: SUMMARY: DATES: Effective September 27, 1972. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 72-20-03 BEECH: Amendment 39-1524. Applies to Models 65-90, 65-A90 and B90 (Serial Numbers LJ-1 thru LJ-501) airplanes and to Models 99, 99A, A99A and B99 (Serial Numbers U-1 thru U-151) airplanes. Compliance: Required as indicated, unless already accomplished. To prevent heater overheat which melts the windshield defroster ducting, damages wiring beneath the instrument panel and fills the cabin with smoke, accomplish the following: A) Effective immediately, operation of the heater is prohibited if the ventilation blower is not functioning. B) Prior to each flight determine that the ventilation blower is operating. NOTE: This determination may be made by checking for air flow out of the air distribution openings in the cockpit and/or by the sound of the blower. C) Within 25 hours' time in service after the effective date of this AD: (1) Remove and replace existing vent blower and combustion differential switches with Beech P/N 90-380010-1 differential pressure switches in accordance with Beechcraft Service Instructions No. 0500-412 or later revision. (2) Inspect the heater fuse to determine that a standard fuse of proper value is installed and if an improper fuse is found, prior to further flight, install standard fuse of proper value. NOTE: Beechcraft Service Instructions No. 0500-412 or later revision lists proper fuses. D) When Paragraph C has been complied with the limitation in Paragraph A may be removed and the check required by Paragraph B may be discontinued. E) Any equivalent method of compliance with this AD must be submitted to and approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region. This amendment becomes effective September 27, 1972. FOOTER:
Document Text
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AD Final Rules - DRS_72-20-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 72-20-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes Subject: Heater Overheat Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/27/1972 Make: Textron Aviation Inc. Model: 65-90 | 65-A90 | 99 | 99A | A99A | B90 | B99 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: 72-20-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1524 AD NUMBER: 72-20-03 SUBJECT HEADING: Airworthiness Directives; BEECH Models 65-90, 65-A90, B90, 99, 99A, A99A and B99 Airplanes ACTION: SUMMARY: DATES: Effective September 27, 1972. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 72-20-03 BEECH: Amendment 39-1524. Applies to Models 65-90, 65-A90 and B90 (Serial Numbers LJ-1 thru LJ-501) airplanes and to Models 99, 99A, A99A and B99 (Serial Numbers U-1 thru U-151) airplanes. Compliance: Required as indicated, unless already accomplished. To prevent heater overheat which melts the windshield defroster ducting, damages wiring beneath the instrument panel and fills the cabin with smoke, accomplish the following: A) Effective immediately, operation of the heater is prohibited if the ventilation blower is not functioning. B) Prior to each flight determine that the ventilation blower is operating. NOTE: This determination may be made by checking for air flow out of the air distribution openings in the cockpit and/or by the sound of the blower. C) Within 25 hours' time in service after the effective date of this AD: (1) Remove and replace existing vent blower and combustion differential switches with Beech P/N 90-380010-1 differential pressure switches in accordance with Beechcraft Service Instructions No. 0500-412 or later revision. (2) Inspect the heater fuse to determine that a standard fuse of proper value is installed and if an improper fuse is found, prior to further flight, install standard fuse of proper value. NOTE: Beechcraft Service Instructions No. 0500-412 or later revision lists proper fuses. D) When Paragraph C has been complied with the limitation in Paragraph A may be removed and the check required by Paragraph B may be discontinued. E) Any equivalent method of compliance with this AD must be submitted to and approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region. This amendment becomes effective September 27, 1972. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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