AD 91-16-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11 | Airworthiness Directives; MITSUBISHI Models YS-11, YS-11A-200, YS-11A-300, YS-11A-500, and YS-11A-600 Series Airplanes |
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11A-200 | Airworthiness Directives; MITSUBISHI Models YS-11, YS-11A-200, YS-11A-300, YS-11A-500, and YS-11A-600 Series Airplanes |
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11A-300 | Airworthiness Directives; MITSUBISHI Models YS-11, YS-11A-200, YS-11A-300, YS-11A-500, and YS-11A-600 Series Airplanes |
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11A-500 | Airworthiness Directives; MITSUBISHI Models YS-11, YS-11A-200, YS-11A-300, YS-11A-500, and YS-11A-600 Series Airplanes |
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11A-600 | Airworthiness Directives; MITSUBISHI Models YS-11, YS-11A-200, YS-11A-300, YS-11A-500, and YS-11A-600 Series Airplanes |
Unsafe Condition
Uncontrolled nose down pitch of the airplane on landing approach during icing conditions due to flap extension beyond 20 degrees in known icing conditions or visible moisture below +5°C (+41°F) OAT.
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Required Actions
Revise the AFM's Operating Limitations Section to restrict flaps to 20 degrees in specified conditions, add a placard near the flap handle, insert specific MHI Transmittal Letters into the AFM, and revise the AFM's Normal Operating Procedures Section with cautionary notes.
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Compliance Time
Within 30 days after March 19, 1991 for paragraph (a), and within 30 days after August 22, 1991 for paragraphs (b) through (e).
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Affected Aircraft
Mitsubishi Heavy Industries, Ltd. Models YS-11, YS-11A-200, YS-11A-300, YS-11A-500, and YS-11A-600 series airplanes, certificated in any category.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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