AD 99-19-06
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11 | Airworthiness Directives; Mitsubishi Model YS-11 and YS-11A Series Airplanes |
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11A-200 | Airworthiness Directives; Mitsubishi Model YS-11 and YS-11A Series Airplanes |
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11A-300 | Airworthiness Directives; Mitsubishi Model YS-11 and YS-11A Series Airplanes |
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11A-500 | Airworthiness Directives; Mitsubishi Model YS-11 and YS-11A Series Airplanes |
| aircraft | Mitsubishi Heavy Industries, Ltd. | YS-11A-600 | Airworthiness Directives; Mitsubishi Model YS-11 and YS-11A Series Airplanes |
Unsafe Condition
Failure to activate airframe pneumatic deicing boots at the first signs of ice accumulation leading to reduced controllability due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle.
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Required Actions
Revise the Airplane Flight Manual (AFM) Limitations Section to require activation of the airframe pneumatic deicing boots at the first sign of ice accretion or upon ice detector annunciation. Include procedures for periodic cycling of the boots to prevent ice bridging and ensure ice shedding.
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Compliance Time
Before further flight
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Affected Aircraft
Mitsubishi Model YS-11 and YS-11A series airplanes (YS-11, YS-11A-200, YS-11A-300, YS-11A-500, YS-11A-600)
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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