Fuel Tank Vent Fire Protection; Correction
The FAA is correcting a final rule published in the Federal Register on June 24, 2016 (81 FR 41200). In that final rule, the FAA amended certain airworthiness regulations for transport category airplanes to require fuel tank designs that prevent a fuel tank explosion caused by the propagation of flames, from external fires, through the fuel tank vents. The final rule requires a delay of two minutes and thirty seconds between exposure of external fuel tank vents to ignition sources and explosions caused by propagation of flames into the fuel tank, thus increasing the time available for passenger evacuation and emergency response. The amendments apply to applications for new type certificates and certain applications for amended or supplemental type certificates. The amendments also require certain airplanes produced in the future and operated by air carriers to meet the new standards. However, in that document, the amendment numbers for the final rules were incorrect, and an airplane model number in a footnote was incorrect. This document now posts the correct amendment numbers and airplane model number in the footnote.
Provision of Navigation Services for the Next Generation Air Transportation System (NextGen) Transition to Performance-Based Navigation (PBN) (Plan for Establishing a VOR Minimum Operational Network)
This action sets forth the Very High Frequency (VHF) Omnidirectional Range (VOR) Minimum Operational Network (MON) policy as proposed in the Proposed Provision of Navigation Services for the Next Generation Air Transportation System (NextGen) Transition to Performance-Based Navigation (PBN) notice of proposed policy published on December 15, 2011 (76 FR 77939). This document provides the discontinuance selection criteria and candidate list of VOR Navigational Aids (NAVAIDs) targeted for discontinuance as part of the VOR MON Implementation Program and United States (U.S.) National Airspace System (NAS) Efficient Streamline Services Initiative. Additionally, this policy addresses the regulatory processes the FAA plans to follow to discontinue VORs.
Airworthiness Directives; Rolls-Royce plc Turbofan Engines
We propose to adopt a new airworthiness directive (AD) for certain Rolls-Royce plc (RR) RB211-Trent 875-17, RB211-Trent 877-17, RB211-Trent 884-17, RB211-Trent 884B-17, RB211-Trent 892-17, RB211- Trent 892B-17, and RB211-Trent 895-17 turbofan engines that have not incorporated RR modification 72-J195 in production or RR Service Bulletin (SB) RB.211-72-J195. This proposed AD was prompted by inspection of RR Trent 800 engines returned from service that revealed flame erosion and axial cracking on the aft face of the stage 3 disk rim of the high-pressure compressor (HPC) stage 1-4 rotor disks shaft. This proposed AD would require machining the HPC stage 3 inner shroud, inspecting the HPC stage 1-4 rotor disks shaft, and replacing the HPC stage 1-4 rotor disks shaft if found defective. We are proposing this AD to prevent uncontained failure of the HPC stage 1-4 rotor disks shaft, damage to the engine, and damage to the airplane.