Airworthiness Directives (ADs) Issued

The Agência Nacional de Aviação Civil (ANAC) (Brazilian Authority) issued the following ADs related to EMB-120 icing:

  • AD 97-06-03R1: This AD mandates the installation of ice detectors.

  • AD 2001-05-02: This AD prohibited the use of autopilot whenever entering ice conditions (Superseded by AD 2001-05-02R1).

  • AD 2001-05-02R1: This AD relieves the prohibition of using the autopilot in icing conditions, provided a low-speed visual/aural alarm system is installed (Superseded by 2001-05-02R2).

  • AD 2001-05-02R2: This AD imposes a modification to the existing low-speed visual/aural alarm system.

The FAA issued the following ADs related to EMB-120 icing:

  • 96-09-24: This AD requires revising the Airplane Flight Manual (AFM) to provide the flight crew with recognition cues for and procedures for exiting severe icing conditions, and to limit or prohibit the use of various flight control devices.

  • 98-15-22: This AD requires a one-time inspection for delamination, erosion, and condition of fillet sealant and conductive edge sealer of the wing and empennage leading edge area behind the de-ice boots, and follow-on corrective actions.

  • 2001-06-18: This AD requires revising the AFM to include requirements for activation of the ice protection systems, and to add information regarding operation in icing conditions; installing an ice detector system; and revising the AFM to include procedures for testing system integrity. This AD also requires installing the ice detector system in accordance with revised procedures.

  • 2001-20-17: This AD requires revising the AFM, installing a placard on the main instrument panel, and removing the "LIGHT-HEAVY" inflation switch of the leading edge deicing boots. This amendment continues to require those actions and adds requirements to install a low speed alarm for icing conditions, to revise the AFM, and to replace an existing placard with a placard that directs the flight crew to activate the deicing boots whenever ice is detected by visual cues or ice detector illumination.

  • 2007-26-21: Icing tunnel tests on an EMB-120 wing section, conducted under a joint Embraer-NASA-- FAA-CTA (Centro Tecnico Aeroespacial) research program well after the EMB-120 was type-certificated, have shown that stick-shaker-to-stick pusher speed margins may drop below the minimum required by the applicable regulations in certain icing conditions. Although flight tests have shown that the aircraft handling qualities are not adversely affected, these reduced speed margins may significantly increase crew workload in certain flight phases. In order to preserve the original certification stick-shaker-to-stick-pusher-margins when operating under the newly defined intercycle icing conditions, an upgraded stall warning computer with new settings for shaker firing angle-of-attack is required to be installed.

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