# Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series Airplanes and Model MD-88 Airplanes
> **Rule** · Final rule. · Published 1999-11-19 · Effective 1999-12-27 · 64 FR 63187
## Document
- **Document number:** 99-30056
- **Category:** airworthiness
- **Manufacturer:** McDonnell Douglas Model DC-9-80 Series
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 64 FR 63187
- **Publication date:** 1999-11-19
- **Effective date:** 1999-12-27
- **FAA docket:** Docket No. 99-NM-05-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-80 series airplanes and Model MD-88 airplanes, that requires a one-time visual inspection to determine whether self-aligning nuts are installed at certain locations of the aft pressure bulkhead tee; and corrective actions, if necessary. This amendment is prompted by reports of failures of certain Hi-Lok pin fasteners of the aft pressure bulkhead tee due to installation of non-self-aligning nuts. The actions specified by this AD are intended to prevent failure of certain Hi-Lok pin fasteners and subsequent gouging of the aft pressure bulkhead tee, which could result in fatigue cracking and reduced structural integrity of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/11/19/99-30056/airworthiness-directives-mcdonnell-douglas-model-dc-9-80-series-airplanes-and-model-md-88-airplanes)
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