# 2026-16507: Helicopter Valves Magnetized by Rogue Diode—FAA Fixes

2026-16507, Airworthiness Directives; Airbus Helicopters, is a Federal Register rule from Transportation Department, Federal Aviation Administration published 2026-08-13, effective 2026-09-17; PRIA reads it as touching household money (as of 2026-08-20).

- Canonical: https://policyrisk.com/federal-register/2026-16507
- As of: 2026-08-20
- Plain-text twin of the page above; the HTML and this file carry the same facts.

## Facts
- Document number: 2026-16507
- Title: Airworthiness Directives; Airbus Helicopters
- Type: Rule
- Agencies: Transportation Department; Federal Aviation Administration
- Citation: 91 FR 52221
- Published: 2026-08-13
- Effective: 2026-09-17
- Comments close: not stated
- Significant: no
- Touches household money: yes
- Regulation identifier numbers: 2120-AA64
- Last updated: 2026-08-20

## In one line

Helicopter Valves Magnetized by Rogue Diode—FAA Fixes

## Summary

The FAA is adopting a new airworthiness directive (AD) for certain Airbus Helicopters Model AS350B2 helicopters. This AD was prompted by a report of magnetization on the solenoid valves for the three main servo-controls, the regulator block, and the tail servo- control due to a diode not properly installed in the hydraulic circuit. This AD requires performing a cut-off test of the rear rotor actuator valve and, depending on the results of the test, performing corrective actions. The FAA is issuing this AD to address the unsafe condition on these products.

## Effects PRIA read

- Mandatory safety test and fixes: cost, medium. If you operate an Airbus Helicopters Model AS350B2, you must perform a cut-off test of the rear rotor actuator valve and, depending on the test results, do corrective actions required by EASA AD 2025-0263. This rule is effective September 17, 2026, and is intended to prevent loss of hydraulic assis…
- Estimated test cost per helicopter: cost, low. The FAA estimates the cut-off test will take 3 work-hours at $85 per hour, costing $255 per AS350B2 helicopter. The FAA estimates this AD affects 12 U.S.-registered helicopters, with an estimated total cost to U.S. operators of $3,060 for the test.
- Cost to replace diode (on-condition): cost, medium. If the cut-off test shows a discrepancy, replacing diode 43D2 is estimated at 1 work-hour ($85) plus $180 in parts, for a total estimated cost of $265 per helicopter. The FAA cannot predict how many helicopters will need this replacement.
- Cost to install missing diode: cost, high. If the diode is missing and must be installed, the FAA estimates 5 work-hours at $85 per hour (labor $425) plus parts costing about $1,000, for a total estimated cost of $1,425 per helicopter. The FAA cannot predict how many helicopters will require this installation.

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## Sources
- [2026-16507 on federalregister.gov](https://www.federalregister.gov/documents/2026/08/13/2026-16507/airworthiness-directives-airbus-helicopters)
- [2026-16507 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2026-08-13/pdf/2026-16507.pdf)

## Related
- [Previous: 2026-16506, Airworthiness Directives; Airbus Helicopters](https://policyrisk.com/federal-register/2026-16506)
- [Next: 2026-16508, Medicaid Program; Prohibition on Federal Medicaid and Children's Health Insuran…](https://policyrisk.com/federal-register/2026-16508)
- [All Federal Register documents](https://policyrisk.com/federal-register)

Source: PRIA, https://policyrisk.com/federal-register/2026-16507 (as of 2026-08-20).