Federal Aviation Administration June 14, 2013 – Federal Register Recent Federal Regulation Documents

A notice of proposed rulemaking published in the Federal Register of March 6, 2013, to establish Class E airspace at Cleveland Regional Jetport, Cleveland, TN, is being withdrawn. Upon review, the FAA found that, for clarity, combining this proposed rulemaking with another proposal to amend existing airspace is necessary.

We propose to adopt a new airworthiness directive (AD) for the MDHI Model MD900 helicopters with certain main rotor blade (MRB) retention bolts (bolts) installed. This proposed AD would require a daily check of the position of each bolt and would also require a daily check and a repetitive inspection for a gap in each bolt. The proposed AD would also require, if necessary, removing and inspecting the bolt for a crack and replacing any cracked bolt with an airworthy bolt. This proposed AD is prompted by multiple reports of in-service bolt failures. The proposed actions are intended to prevent failure of a bolt, which could lead to loss of MRB structural integrity and subsequent loss of control of the helicopter.

We are adopting a new airworthiness directive (AD) for certain Engine Alliance GP7270 and GP7277 turbofan engines. This AD was prompted by damage to the high-pressure compressor (HPC) stage 7-9 spool caused by failure of the baffle plate feature on affected HPC stage 6 disks. This AD requires initial and repetitive borescope inspections of the baffle plate feature and removal from service of the HPC stage 6 disk if the plate is missing material. This AD also requires mandatory removal from service of these HPC stage 6 disks at the next HPC module exposure. We are issuing this AD to prevent failure of the HPC stage 7-9 spool, uncontained engine failure, and damage to the airplane.

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 777-200 and -300 series airplanes. This AD was prompted by reports of hydraulic fluid contamination (including contamination caused by hydraulic fluid in its liquid, vapor, and/or solid (coked) form) found in the strut forward dry bay. This AD requires repetitive general visual inspections of the strut forward dry bay for the presence of hydraulic fluid, and related investigative and corrective actions (including checking drain lines for blockage due to hydraulic fluid coking, and cleaning or replacing drain lines to allow drainage) if necessary. We are issuing this AD to detect and correct hydraulic fluid contamination of the strut forward dry bay, which could result in hydrogen embrittlement of the titanium forward engine mount bulkhead fittings, and consequent inability of the fittings to carry engine loads, resulting in engine separation. Hydraulic embrittlement also could cause a through-crack formation across the fittings through which an engine fire could breach into the strut, resulting in an uncontained strut fire.