Warns Dreamliner Pilots Not To Use Abrupt Control Inputs In Case Of Erroneous Airspeed Indications

The FAA states they are adopting a new airworthiness directive (AD) for all Boeing Company Model 787-8 and 787-9 airplanes. This AD requires revising the airplane flight manual (AFM) to instruct the flightcrew to avoid abrupt flight control inputs in response to sudden drops in airspeed, and to reinforce the need to disconnect the autopilot before making any manual flight control inputs.

This AD was prompted by reports indicating that in certain weather conditions with high moisture content or possible icing, erroneous low airspeed may be displayed to the flightcrew before detection and annunciation via engine-indicating and crew-alerting system (EICAS) messages.

The FAA says they are issuing this AD to ensure that the flightcrew avoids abrupt pilot control inputs in response to an unrealistic, sudden drop in displayed airspeed at high actual airspeed. Abrupt pilot control inputs in this condition could exceed the structural capability of the airplane.

The FAA also says it has received reports of airspeed anomalies on these airplanes that may be associated with water and ice affecting the three Pitot tubes. It’s reported that the displayed airspeed rapidly dropped below the correct indication. The concern is that rapid pilot reaction to a low indicated airspeed could cause the pilot to place the airplane and a significant nose down position resulting in increased stress on the airframe.

The Wall Street Journal reported that a Boeing spokeswoman said the company is fully supporting the FAA directives and has worked closely with the FAA to monitor the fleet and take appropriate actions.

(Image from file)

FMI: Aviation-Safety.net