AD 99-14-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Piper Aircraft Inc. | PA-23 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-23-160 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-23-235 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-23-250 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-23-250 (Navy UO-1) | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-30 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-31 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-31-300 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-31-325 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
| aircraft | Piper Aircraft Inc. | PA-31-350 | Airworthiness Directives; The New Piper Aircraft, Inc. PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 Series Airplanes |
Unsafe Condition
Severe icing conditions beyond certification limits may cause ice buildup exceeding ice protection system capability or ice forming aft of protected surfaces, degrading performance and controllability.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Revise the AFM Limitations Section to include specific severe icing warnings and procedures, including immediate priority handling requests, autopilot restrictions, and operational prohibitions in severe icing conditions. Ensure flight crews are informed of changes.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 30 days after March 13, 1997 for most models, except PA-31P, PA-31T, PA-31T1, PA-31T2, PA-31P-350 which must comply within 30 days after the AD's effective date (August 17, 1999).
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Piper PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, PA-42 series models including PA-31P, PA-31T, PA-31T1, PA-31T2, PA-31P-350, all serial numbers.
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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