# Proposed AD FAA-2016-3702: The Boeing Company Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2016-18-04
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: February 25, 2016, 81 FR 9370
- Comments due: April 11, 2016
- Became: [AD 2016-18-04](https://openairdocs.org/ad/2016-18-04)
- Docket: FAA-2016-3702 (https://www.regulations.gov/docket/FAA-2016-3702, where comments are filed)
- Project: 2015-NM-103-AD
- FR document: 2016-03690
- Official PDF: https://openairdocs.org/files/sha256/31/c3/31c3783a00b5c9efcd67cb9324114ee8426daed635981a55405ca1825639a165 (from https://www.govinfo.gov/content/pkg/FR-2016-02-25/pdf/2016-03690.pdf)
- Federal Register: https://www.federalregister.gov/documents/2016/02/25/2016-03690/airworthiness-directives-the-boeing-company-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0F676438D830392686257F6400553E16.0001
- Page: https://openairdocs.org/proposed/FAA-2016-3702

## Summary

We propose to supersede Airworthiness Directive (AD) 2013-24- 12, which applies to all The Boeing Company Model 747-8 and 747-8F airplanes. AD 2013-24-12 currently requires repetitive ultrasonic or dye penetrant inspections for cracking of the barrel nuts and bolts on each forward engine mount, and related investigative and corrective actions if necessary. Since we issued AD 2013-24-12, we have determined that it is necessary to mandate the installation of new barrel nuts or new inspections to adequately address the unsafe condition. This proposed AD would retain the requirements of AD 2013-24-12 and add requirements to install new barrel nuts at the forward engine mounts; or identify the part number of the barrel nuts, inspect affected barrel nuts for gaps of the strut bulkhead and forward engine mount, and do related investigative and corrective actions if necessary. This proposed AD would also remove airplanes from the applicability. We are proposing this AD to detect and correct cracked barrel nuts on a forward engine mount, which could result in reduced load capacity of the forward engine mount, separation of an engine under power from the airplane, and consequent loss of control of the airplane.

## Notices in this docket

- Feb 25, 2016: Notice of proposed rulemaking (NPRM). (first notice), FR document 2016-03690, comments due Apr 11, 2016 (https://www.federalregister.gov/documents/2016/02/25/2016-03690/airworthiness-directives-the-boeing-company-airplanes)

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