Regulatory Brief -- AOPA petitions FAA to rescind Precise Flight standby vacuum system AD and reopen public comment period

December 20, 1999

Federal Aviation Administration
Aircraft Certification Service
Small Airplane Directorate
Attn: Michael Gallagher (ACE-100)
901 Locust St., Room 307
Kansas City, MO 64106


The Aircraft Owners and Pilots Association (AOPA), representing the aviation interests of over 355,000 pilots and aircraft owners, submits the following petition for reconsideration of a final rule airworthiness directive (AD) under the authority of 14 C.F.R. �11.93. On November 30, 1999, the FAA published, as final rule, AD 99-24-10 in the Federal Register. The AD calls for repetitive inspections and repetitive flight tests of Precise Flight Inc. Model SVS III Standby Vacuum systems. AOPA requests that this AD be rescinded so that the public may have more time to comment on the complete provisions of the AD, specifically the repetitive flight testing requirements contained in section 3.3 of Precise Flight Inc. Installation Report No. 50050.

On July 7, 1999 the FAA published notice of proposed rulemaking (NPRM) 98-CE-87-AD which proposed the above referenced AD. AOPA elected not to comment on the provisions contained in the NPRM on the grounds that inspection of the cables, lines, fittings, and valves of Precise Flight Inc. Model SVS III Standby Vacuum Systems is an appropriate way to ensure proper continued operation of these systems. However, in the NPRM, the FAA mandates that all inspections and tests must be conducted in accordance with Precise Flight Instructions for Continued Airworthiness (Section 3.3 of Installation Report No. 50050), revision 25, dated August 26, 1996. AOPA feels that the repetitive flight testing requirements contained in this document are particularly contentious, may more than double the compliance cost of this AD, and may ultimately cause affected aircraft owners to remove these systems from their aircraft.

Many mechanics estimate that the preparatory work required to prep an aircraft for the

flight testing provisions contained in Section 3.3 of Precise Flight Inc. Installation Report No. 50050 may require up to two hours labor. Preparing the aircraft for return to service after the inspections could easily double this estimate. Aircraft owners and operators estimate that the flight testing at all required altitudes may take an additional two hours. Ultimately, Precise Flight�s testing requirements may add as many as six hours labor to the total cost of AD compliance for each affected aircraft, resulting in a three fold increase in the total cost of AD compliance.

The FAA estimates that compliance with the inspection provisions of this AD will cost approximately $180 (3 hours labor at $60/hr.). The flight testing requirements set forth in Precise Flight�s Instructions for continued airworthiness raise this figure by another $360 (6 hours labor @ $60/hr.), resulting in a total annual compliance cost of $540. Such a dramatic increase in compliance cost is alarming, especially when one considers that a new SVS III standby vacuum system lists for $429.

AOPA fails to see any benefit in repeating a testing procedure designed to test the standby vacuum system�s operational parameters directly following its installation. In numerous e-mail communications with owners of Precise Flight standby vacuum systems, Precise Flight indicated that the flight test requirements were revamped to ensure that pilots received adequate training in the operation of their systems. In an e-mail to a Mooney operator�s newsgroup dated December 15, 1999, Mr. Scott Philiben of Precise Flight stated "The Flight Test procedure was rewritten to insure that the pilot was familiar with system operation. The purpose of the flight test is pilot recurrent training."

AOPA maintains that the repetitive flight testing requirements contained in Precise Flight�s Instructions for continued airworthiness are, in fact, an operational issue rather than an airworthiness concern. Further, AOPA maintains that operational issues should not be included in an AD. AOPA and the FAA have experienced tremendous success in reducing accident rates due to specific operational and airworthiness concerns simply by informing and educating the general aviation pilot and aircraft owner communities of specific problems. We believe similar success could be achieved in this instance.

Historically, AOPA and the AOPA Air Safety Foundation have advocated the use of standby vacuum systems as a cost-effective operational adjunct for any pilot operating in instrument meteorological conditions (IMC). In the event of a failure of the primary vacuum system and associated gyro instruments in IMC, standby vacuum systems can reduce pilot workload and decrease the likelihood of spatial disorientation or other physiological phenomena. For these reasons, AOPA maintains that a standby vacuum system can add significantly to the safety of flight. Unfortunately, the expense of complying with the provisions of this AD will result in a large number of aircraft owners removing these systems from their aircraft.

In summary, AOPA maintains that the flight test provisions included in Precise Flight�s Instructions for Continued Airworthiness will raise the compliance cost of this AD to more than the retail value of a new SVS III standby vacuum system. These high compliance costs will prompt the majority of owners/operators currently using these systems to remove the system from their aircraft. AOPA maintains that reconsideration of this final rule is in the public�s best interest, as it will ensure the continued use of standby vacuum systems, thus enhancing aviation safety. For these reasons, AOPA requests that the FAA rescind final rule AD 99-24-05 and reissue the proposed AD for public comment.

Thank you for your time and consideration in this matter. AOPA stands ready to assist the FAA in reconsidering the issuance of this AD.


Dennis E. Roberts
Vice President/Executive Director
Government and Technical Affairs