Current Regulatory Activity

Air Safety Week, August 9, 2004

Pay particular attention to the July 30 final rule delaying fuel and electrical system initiatives, and the July 27 final rule on the center and wing tank float switch wiring problem. Other items are included to complement the discussion of the July 30 final rule.

Date posted on Federal Register and Document Type: July 26 Notice of Proposed Rulemaking (NPRM) FR Doc 04-16917 Structural safety Summary of Situation: BAE Systems model BAe 146 and Avro 146-RJ, requiring repetitive inspections to detect cracking and fatigue of the upper fuselage rear skin, to prevent sudden loss of cabin pressure.

Action Date & Comments: Comments due Aug. 25. NPRM cites the potential for "joining of those cracks." The wording suggests dangerous multi-site fatigue damage of the type that blew the upper fuselage off an Aloha Airlines B737 in 1988. The NPRM says, "For areas where no crack is found, repeat the inspection at intervals not to exceed 8,000 landings." This interval equates roughly to 2,000 in-service days and 2,150 calendar days - or nearly six years and 24,000 flight hours. It is difficult to imagine that a known cracking problem would be incapable of initiating and propagating to danger level inside that period. Crack growth rates are not always linear. Manufacturer's service bulletin (SB) provides repair instructions. Action affects 55 airplanes in U.S. registry.

Date posted on Federal Register and Document Type: July 27 Final Rule FR Doc 04-16676 Airworthiness directive (AD) AD 2004-15-04 Fuel system safety Summary of Situation: Boeing [BA] B737-200, -300, -400 & -500 airplanes. Requires replacement of center and wing tank float switches, and installing conduit in the center tank, to prevent an ignition source inside the tanks that could cause a fire or explosion.

Action Date & Comments: Effective Aug. 31. Two-year compliance time. The Federal Aviation Administration (FAA) rejected calls for three- and four-year compliance times. Two commenters to the proposed rule suggested that transient suppression devices (TSDs) should be allowed as an alternate means of compliance. FAA agreed "in principle" but said TSDs for B737 classics have not yet been approved for installation. One commenter said the float switch replacement was inconsistent with SFAR 88, the rule on fuel system safety, because the new 28-volt DC switch "exceeds the intrinsically safe level for equipment located in fuel tanks, as defined by SFAR 88." The FAA demurred, saying the new float switch provides "an equivalent level of safety" because of its hermetically sealed design. Moreover, the new switch will be considered a Critical Design Configuration Control Limitation (CDCCL). As outlined in this publication, the CDCCL concept introduced in a May 28 FAA notice of proposed policy is sweeping in scope, requiring strict adherence

Date posted on Federal Register and Document Type: July 29 Final Rule FR Doc 04-16916 AD 2004-15-13 Electrical system safety

Summary of Situation: Douglas-built DC-9 and MD-80 series airplanes. Requires replacement or removal of ribbon heaters on the lavatory water lines to prevent arcing and potential fire under the sink.

Action Date & Comments: Effective Sept. 2. Accomplish within 18 months. Recall the significant arcing damage to the water line and adjacent area in two Air Canada B767s (see ASW, June 10, 2002). Qantas long ago changed to internal pipe heating elements. Action affects 1,180 airplanes worldwide, of which 724 are in U.S. registry.

Date posted on Federal Register and Document Type: July 30 Final Rule FR Doc 04-17221 AD 2004-15-16 Fuel system safety

Summary of Situation: Airbus A310 airplanes. Requires modification to ensure that fuel quantity indication system (FQIS) wires are properly separated from wires carrying 115-volt AC power.

Action Date & Comments: Effective Sept. 3. Accomplish within 4,000 flight hours (about two years service). Damage to the wiring could lead to a short circuit and fire. Not the first time we have reported on the inadequate separation of low-power signal wires (such as FQIS) with high power wires. Recall that TWA Flight 800 exploded due to high power current crossing over to FQIS wiring going to the center wing tank. Action affects 46 airplanes in U.S. registry.

Date posted on Federal Register and Document Type: July 30 Final rule; request for comments FR Doc 04-17188 Docket No. FAA-2004-17681 Fuel system safety, electrical system safety, and aging airplane structural safety, notably regarding fatigue and corrosion

Summary of Situation: The FAA announces significant schedule slips in order to give the industry more time to comply with a variety of emerging mandates. This document answers much of the uncertainty surrounding new maintenance and inspection requirements highlighted recently in this publication (see ASW, June 21). A number of programs were progressing in what might be called "parallel universes," with significant potential to burden operators with conflicting requirements. This document reflects the FAA's attempt to bring the parallel tracks into alignment, in the form of a program that better integrates the various parts. The various programs involved are: 1. Fuel system safety program. 2. Enhanced airworthiness program for airplane systems (EAPAS). 3. The aging airplane program (i.e., those with 14 or more years service). 4. A corrosion prevention and control program (CPCP). 5. A widespread fatigue damage (WFD) program. Affects thousands of airplanes.