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FAA
Federal Aviation Administration Department of Transportation
Aviation Safety
AIRWORTHINESS DIRECTIVE
Generated by Aircraft-logs.com — March 22, 2026

AD 47-20-09 ACTIVE

Voltage regulator check
Key Information
AD Number 47-20-09 Status Active
Effective Date Not specified Issue Date Not specified
Docket Number Unknown Amendment N/A
Product Type ["Aircraft"] Product Subtype ["Small Airplane"]
CFR Part --- - Part 39 CFR Section N/A
Citation This information is not available.
Applicability
Manufacturer(s) Univair Aircraft Corporation
Model(s) 415-C 415-CD 415-D
Regulatory Text

47-20-09 ERCO: (Was Service Note 1 of AD-718-6.) Applies to 415-C, -CD and -D Aircraft.
Compliance required at each 100-hour inspection and immediately after each electrical system malfunction.
Check the operation of the voltage regulator by observing the ammeter reading after starting and until the battery becomes charged. A normal operation would indicate a charging rate up to 11-13 amperes for periods of time up to 20 minutes after starting. The charging rate should reduce to 2 amperes or less within 2 hours or operation.
(Ercoupe Service Department Memorandum No. 23 covers this same subject.)

AD 47-20-09 — Voltage regulator check
Printed from Aircraft-logs.com — 03/22/2026