# Proposed AD 98-18158: McDonnell Douglas Model DC-8 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Comment period closed
- Action: Notice of proposed rulemaking (NPRM).
- Published: July 9, 1998, 63 FR 37074
- Comments due: August 24, 1998
- FR document: 98-18158
- Official PDF: https://openairdocs.org/files/sha256/a9/9e/a99e4581c5877edf406389fcf28d78ac58f1a18a95eae5a223f30649521f7530 (from https://www.govinfo.gov/content/pkg/FR-1998-07-09/pdf/98-18158.pdf)
- Federal Register: https://www.federalregister.gov/documents/1998/07/09/98-18158/airworthiness-directives-mcdonnell-douglas-model-dc-8-series-airplanes
- Page: https://openairdocs.org/proposed/98-18158

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Model DC-8 series airplanes. Among other things, this proposal would require repetitive leak tests of the lavatory drain systems and repair, if necessary; installation of a lever lock cap, vacuum breaker check valve or flush/ fill line ball valve on the flush/fill line; periodic seal changes; and replacement of ``donut'' type waste drain valves installed in the waste drain system. This proposal is prompted by continuing reports of damage to engines, airframes, and to property on the ground, caused by ``blue ice'' that forms from leaking lavatory drain systems on transport category airplanes and subsequently dislodges from the airplane fuselage. The actions specified by this proposed AD are intended to prevent such damage associated with the problems of ``blue ice.''

## Notices in this docket

- Jul 9, 1998: Notice of proposed rulemaking (NPRM). (first notice), FR document 98-18158, comments due Aug 24, 1998 (https://www.federalregister.gov/documents/1998/07/09/98-18158/airworthiness-directives-mcdonnell-douglas-model-dc-8-series-airplanes)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.