Discussion
What events have caused this AD? The manufacturer has reported that the TAWS8000 TAWS causes altitude errors in other instruments when both the TAWS and any other device are connected to the same baro set potentiometer. The unsafe condition was discovered during the installation of a TAWS8000 TAWS in a Cessna 500 series airplane. The TAWS8000 TAWS was connected to the baro set potentiometer output of a Honeywell (Sperry) BA-141 altimeter that was also connected to a Honeywell AZ-241 Air Data Computer. The altimeter showed that the aircraft was 60 feet higher than the actual altitude. This unsafe condition was confirmed with the laboratory test of a TAWS8000 TAWS installation.
What are the consequences if the condition is not corrected? This condition, if not corrected, could cause the pilot to make flight decisions that put the airplane in unsafe flight conditions.
Is there service information that applies to this subject? Goodrichhas issued Service Memo SM 134, dated May 2, 2003.
What are the provisions of this service information? The service memo specifies the following information:
The TAWS8000 should not be connected to a baro set potentiometer if that potentiometer is also connected to any other device; and
In existing installations where both the TAWS and any other device are connected to the same baro set potentiometer, the TAWS8000 should be removed from the aircraft.
The FAA's Determination and an Explanation of the Provisions of This AD
What has FAA decided? The FAA has reviewed all available information, including the service information referenced above; and determined that:
The unsafe condition referenced in this document exists or could develop on type design airplanes equipped with a Goodrich TAWS8000 TAWS that incorporates hardware "Mod None", "Mod A", or "Mod B";
Any airplane with one of these TAWS8000 TAWS units should have the actions specified in the above service memo incorporated; and
AD action should be taken in order to correct this unsafe condition.
What does this AD require? This AD:
Requires inspection of the TAWS8000 TAWS to determine if both the TAWS8000 TAWS and any other device are connected to the same baro set potentiometer;
Requires removal of any TAWS8000 TAWS with such an installation configuration, which includes capping and stowing the connecting wires; and
Prohibits the future installation of any TAWS8000 TAWS that incorporates hardware "Mod None", "Mod A", or "Mod B'.
In preparation of this rule, we contacted type clubs and aircraft operators to obtain technical information and information on operational and economic impacts. We did not receive any information through these contacts. If received, we would have included, in the rulemaking docket, a discussion of any information that may have influenced this action.
How does the revision to 14 CFR part 39 affect this AD? On July 10, 2002, FAA published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relates to special flight permits, alternative methods of compliance, and altered products. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.
Will I have the opportunity to comment prior to the issuance of the rule? Because the unsafe condition described in this document could result in the pilot making flight decisions that put the airplane in unsafe flight conditions, we find that notice and opportunity for public prior comment are impracticable. Therefore, good cause exists for making this amendment effective in less than 30 days.
Comments Invited
How do I comment on this AD? Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, FAA invites your comments onthe rule. You may submit whatever written data, views, or arguments you choose. You need to include the rule's docket number and submit your comments to the address specified under the caption ADDRESSES. We will consider all comments received on or before the closing date specified above. We may amend this rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether we need to take additional rulemaking action.
Are there any specific portions of the AD I should pay attention to? We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. You may view all comments we receive before and after the closing date of the rule in the Rules Docket. We will file a report in the Rules Docket that summarizes each FAA contact with the public that concerns the substantive parts of this AD.
How can I be sure FAA receives my comment? If you want us to acknowledge the receipt of your comments, you must include a self- addressed, stamped postcard. On the postcard, write "Comments to Docket No. 2003-CE-25-AD." We will date stamp and mail the postcard back to you.
Regulatory Impact
Does this AD impact various entities? These regulations will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, FAA has determined that this final rule does not have federalism implications under Executive Order 13132.
Does this AD involve a significant rule or regulatory action? We have determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a significant regulatory action under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket (otherwise, an evaluation is not required). A copy of it, if filed, may be obtained from the Rules Docket.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by Reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
39.13 [Amended]
2. FAA amends 39.13 by adding a new airworthiness directive (AD) to read as follows: