Federal Aviation Administration August 21, 2008 – Federal Register Recent Federal Regulation Documents

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Cessna Model 560 airplanes. The existing AD currently requires installing new minimum airspeed placards to notify the flightcrew of the proper airspeeds for operating in both normal and icing conditions. The existing AD also requires revising the airplane flight manual to provide limitations and procedures for operating in icing conditions, for operating with anti-ice systems selected ``on'' independent of icing conditions, and for recognizing and recovering from inadvertent stall. The existing AD also provides an optional terminating action for the placard installation. This proposed AD would require the previously optional terminating action. This proposed AD results from an evaluation of in-service airplanes following an accident. The evaluation indicated that some airplanes might have an improperly adjusted stall warning system. We are proposing this AD to prevent an inadvertent stall due to the inadequate stall warning margin provided by an improperly adjusted stall warning system, which could result in loss of controllability of the airplane.

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all Honeywell FMSs served by Honeywell NZ-2000 navigation computers and IC-800 integrated avionics computers. The existing AD currently requires identifying affected computers by part number and software modification level and revising the Limitations section of applicable airplane flight manuals to provide procedures for retaining optimum position determination and intended navigation. This proposed AD would require uploading new software, which would terminate the existing requirements. This proposed AD results from reports of in-flight unannunciated shifts of computed position in airplanes with the subject FMS computers. We are proposing this AD to prevent a shift in the FMS computed position, which could result in uncommanded deviations from the intended flight path of the airplane and, if those deviations are undetected by the flight crew, compromised terrain/traffic avoidance.