AD 90-15-18
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Textron Aviation Inc. | 99 | Airworthiness Directives; BEECH Models 99, 99A, and A99A Airplanes |
| aircraft | Textron Aviation Inc. | 99A | Airworthiness Directives; BEECH Models 99, 99A, and A99A Airplanes |
| aircraft | Textron Aviation Inc. | A99A | Airworthiness Directives; BEECH Models 99, 99A, and A99A Airplanes |
| aircraft | Textron Aviation Inc. | B99 | Airworthiness Directives; BEECH Models 99, 99A, and A99A Airplanes |
Unsafe Condition
Cracks or nicks in the vertical stabilizer main spar at each side of the bend location could lead to loss of structural integrity.
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Required Actions
Visually inspect the vertical fin main spar using a magnifying glass for cracks or nicks. Repair or replace the spar if cracks are found, and replace the vertical fin assembly if cracks exceed 0.25 inches or are present in both spar flange and angle doubler. Replace the vertical fin or install a plate doubler within 500 hours TIS or 20,000 hours TIS on the original stabilizer.
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Compliance Time
Within the next 50 hours TIS from the effective date, and thereafter at intervals not to exceed 500 hours TIS. For Paragraph (d), within 500 hours TIS after the effective date or upon accumulation of 20,000 hours TIS on the original vertical stabilizer, whichever occurs later.
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Affected Aircraft
BEECH Models 99, 99A, A99A (Serial Numbers U-1 through U-147, except U-146); and B99 (S/N U-146 through U-151, except U-147)
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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