AD 99-19-17
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Lockheed Martin Corporation | 1329-23A | Airworthiness Directives; Lockheed Model 1329-23 and 1329-25 Series Airplanes |
| aircraft | Lockheed Martin Corporation | 1329-23D | Airworthiness Directives; Lockheed Model 1329-23 and 1329-25 Series Airplanes |
| aircraft | Lockheed Martin Corporation | 1329-23E | Airworthiness Directives; Lockheed Model 1329-23 and 1329-25 Series Airplanes |
| aircraft | Lockheed Martin Corporation | 1329-25 | Airworthiness Directives; Lockheed Model 1329-23 and 1329-25 Series Airplanes |
Unsafe Condition
Failure to activate the airframe pneumatic deicing boots at the first signs of ice accumulation in icing conditions, leading to reduced controllability due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Revise the Airplane Flight Manual (AFM) Limitations Section to include requirements for activating the wing and tail pneumatic deicing boots at the first sign of ice formation or ice detector annunciation, and specify continued operation in automatic cycling mode or manual cycling as needed. The system may only be deactivated after completing an entire deicing cycle post-icing conditions.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 10 days after the effective date of this AD (December 27, 1999).
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Affected Aircraft
Lockheed Model 1329-23A, 1329-23D, 1329-23E, and 1329-25 series airplanes equipped with pneumatic deicing boots, 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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