Confused by FAA regs? One wrong move sidelines your IFR flying.

Ever dug into §91.411 and §91.413 only to feel buried in appendices? You’re not alone—many owners overlook details that keep them legal.

These rules mandate 24-month inspections for pitot-static systems (§91.411) and transponders (§91.413), with exact standards in Part 43 Appendices E and F. Proper records per §43.9 seal the deal.

Breaking down the regs without the headache

§91.411: Altimeter System and Altitude Reporting Equipment Tests

Covers altimeters, static systems, and encoders—tolerances like ±125 feet, leak checks, and correspondence tests.

Key Requirements:

• 24-month inspection interval for IFR operations
• Tests performed per Part 43 Appendix E standards
• Includes altimeter, static system, and automatic pressure altitude reporting systems
• Must be performed by appropriately certified facilities

§91.413: ATC Transponder Tests and Inspections

Hits transponders: Frequency accuracy, reply rates, suppression. Only authorized personnel sign off.

Key Requirements:

• 24-month inspection interval
• Tests performed per Part 43 Appendix F standards
• Covers Mode A, Mode C, and Mode S transponders
• Verifies proper encoding and transmission

§43.9: Content, Form, and Disposition of Records

Records must detail everything—who performed the work, what was done, methods used, and approval signatures.

Required Documentation:

• Description of work performed
• Date work completed
• Name and certificate information of person performing work
• Signature and certificate number
• Reference to acceptable data used

The payoff for mastering these rules

Compliance means uninterrupted IFR ops and peace of mind. Owners who understand triggers—like post-maintenance re-tests—stay ahead and avoid fines.

Common Compliance Triggers

• 24-month interval expiration - Primary inspection requirement
• Equipment installation or alteration - Requires new inspection
• Equipment malfunction or repair - May require re-inspection
• Aircraft modification affecting static system - Triggers testing

Tolerance Standards

Part 43 Appendix E (Pitot-Static):

• Altimeter: ±20 to ±125 feet depending on altitude
• Static system leak test: Maximum allowable leakage rates
• Automatic pressure altitude reporting: ±125 feet

Part 43 Appendix F (Transponder):

• Radio frequency stability
• Suppression capability
• Power output measurements
• Reply efficiency standards

Take charge of your compliance now.

Review your logs and consult a pro today to ensure full adherence to 91.411, 91.413, and record-keeping rules—keep your wings legal.