# Proposed AD 99-NM-320-AD: Boeing Model 737-100 and-200 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-15-18
- Action: Notice of proposed rulemaking (NPRM).
- Published: March 15, 2000, 65 FR 13919
- Comments due: May 1, 2000
- Became: [AD 2000-15-18](https://openairdocs.org/ad/2000-15-18)
- Docket: 99-NM-320-AD
- FR document: 00-6333
- Official PDF: https://openairdocs.org/files/sha256/6f/ea/6feac2592837de74d7573fefefc9e95158ec0b7e716d505b2fe3aeabb72da081 (from https://www.govinfo.gov/content/pkg/FR-2000-03-15/pdf/00-6333.pdf)
- Federal Register: https://www.federalregister.gov/documents/2000/03/15/00-6333/airworthiness-directives-boeing-model-737-100-and-200-series-airplanes
- Page: https://openairdocs.org/proposed/99-NM-320-AD

## Summary

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 737- 100 and -200 series airplanes, that currently requires inspections to detect cracking of the support fittings of the Krueger flap actuator; and, if necessary, replacement of existing fittings with new steel fittings and modification of the aft attachment of the actuator. That AD also provides for an optional terminating modification that constitutes terminating action for the repetitive inspections. This action would mandate accomplishment of the previously optional terminating action. This proposal is prompted by reports of cracking due to fatigue and stress corrosion of the support fittings of the Krueger flap actuator. The actions specified by the proposed AD are intended to prevent such cracking, which could result in fracturing of the actuator attach lugs, separation of the actuator from the support fitting, severing of the hydraulic lines, and resultant loss of hydraulic fluids. These conditions, if not corrected, could result in possible failure of one or more hydraulic systems, and consequent reduced controllability of the airplane.

## Notices in this docket

- Mar 15, 2000: Notice of proposed rulemaking (NPRM). (first notice), FR document 00-6333, comments due May 1, 2000 (https://www.federalregister.gov/documents/2000/03/15/00-6333/airworthiness-directives-boeing-model-737-100-and-200-series-airplanes)

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