Airworthiness Directive · Amendment 39-18067 · Navigation
Airbus Airplanes
Superseded. A later AD replaced this one: AD 2017-16-12. Comply with the one in force.
This AD applies to the Airbus airplanes, certificated in any category, identified in paragraphs (c)(1), (c)(2), (c)(3), and (c)(4) of this AD.
(1) All Model A318-111, -112, -121, and -122 airplanes.
(2) All Model A319-111, -112, -113, -114, -115, -131, -132, and -133 airplanes.
(3) All Model A320-211, -212, -214, -231, -232, and -233 airplanes.
(4) All Model A321-111, -112, -131, -211, -212, -213, -231, and -232 airplanes.
We are adopting a new airworthiness directive (AD) for all Airbus Model A318, A319, A320, and A321 series airplanes. This emergency AD was sent previously to all known U.S. owners and operators of these airplanes. This AD requires revising the airplane flight manual to advise the flightcrew of emergency procedures for abnormal Alpha Protection (Alpha Prot). This AD was prompted by a report of Angle of Attack (AoA) probes jamming on an in-service Airbus Model A321 airplane. Jamming of the two AoA probes during climb is attributed to water freezing under the AoA vane slinger, and led to activation of the Alpha Prot while the Mach number increased, which resulted in an airplane pitch down per design. We are issuing this AD to ensure that the flightcrew has procedures to counteract the pitch down order due to abnormal activation of the Alpha Prot. An abnormal Alpha Prot, if not corrected, could result in loss of control of the airplane.
Within 2 days after the effective date of this AD, revise the AFM to incorporate procedures to address undue activation of Alpha Prot by inserting the text specified in figure 1 to paragraph (g) of this AD into the Emergency Procedures section of the applicable AFM, to advise the flightcrew of emergency procedures for abnormal Alpha Prot. This may be accomplished by inserting a copy of this AD into the AFM. When a statement identical to the text specified in figure 1 to paragraph (g) of this AD is included in the general revisions of the AFM, the general revisions may be inserted in the AFM, and the text specified in figure 1 to paragraph (g) of this AD may be removed.
| • At any time, with a speed above VLS, if the aircraft goes to a continuous nose down pitch rate that cannot be stopped with backward sidestick inputs, immediately: |
| Keep on one ADR. |
| Turn off two ADRs. |
| • If the Alpha Max strip (red) hides completely the Alpha Prot strip (black and amber) in a stabilized wings-level flight path (without an increase in load factor): |
| Keep on one ADR. |
| Turn off two ADRs. |
| In case of dispatch with one ADR inoperative, switch only one ADR to OFF. |
| • CAUTION RISK OF ERRONEOUS DISPLAY OF THE VSW STRIP (RED AND BLACK) |
| Consider using the Flight Path Vector (FPV). |
| • If the Alpha Prot strip (black and amber) rapidly moves by more than 30 kt during flight maneuvers (with an increase in load factor), with AP ON and speed brakes retracted: |
| Keep on one ADR. |
| Turn off two ADRs. |
| In case of dispatch with one ADR inoperative, switch only one ADR to OFF. |
| CAUTION RISK OF ERRONEOUS DISPLAY OF THE VSW STRIP (RED AND BLACK) |
| Consider using the Flight Path Vector (FPV). |
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
