The bulletin
Text extracted from the PDF.
SPECIAL
AIRWORTHINESS
INFORMATION
BULLETIN Aircraft Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration No. CE-03-21 February 12, 2003 We post SAIBs on the internet at "av-info.faa.gov" This is information only. Recommendations are not mandatory.
Introduction This Special Airworthiness Information Bulletin (SAIB) advises you, owners and operators of SAAB 340 (Fairchild) airplanes with Rockwell Collins Air Data Computers, ADC-85A, CPN 822-0370- 113/-123 installed, that Airworthiness Directive (AD) 2002-14-19, dated July 15, 2002, is not applicable to your aircraft.
Background An undesirable Rockwell Collins ADC-85A flag operation may cause flight crews to deselect a valid alternate static air source during the first 11 seconds that the ADC flag is displayed. It may also cause confusion when reselecting the previously unflagged normal static air source - as this may also result in the ADC flag being displayed for the first 11 seconds. This issue is limited to aircraft that provide “Normal/Alternate Air” static source selection capability.
We issued AD 2002-14-19 in response to this problem. As part of the NPRM comments, the aircraft manufacturer stated that the SAAB 340 aircraft design does not allow switching between alternate static sources. In the comment response we concurred with Saab and removed the aircraft from the applicability list, but did not remove the Rockwell Collins ADC-85A, CPN 822-0370-113/-123 from the equipment list in the AD. Rockwell Collins has indicated that those part numbers are unique to the SAAB 340 installations.
Recommendations Owners and operators of SAAB 340 airplanes with ADC-85A (CPN 822-0370-113/-123) with SB 58, do not need to comply with AD 2002-14-19.
For Further Information Contact Roger A. Souter, Aerospace Engineer, Wichita Aircraft Certification Office (ACE-116W), 1801 Airport Road, Room 100, Wichita, KS 67209, telephone (316) 946-4134, fax (316) 946-4407, email:
roger.souter@faa.gov.