DISTRIBUTION A. Approved for Public Release; Distribution Unlimited.
EZ-SB-20-02, Page 1 of 7
Number: EZ-SB-20-02
Date: 16 March 2020
Subject: Guidance for the Classification of Aircraft Structural Critical Parts
References:
1. MIL-STD-1530D w/CHANGE 1, “Aircraft Structural Integrity Program (ASIP)”, 13
October 2016
2. JSSG-2006, “Department of Defense Joint Service Specification Guide, Aircraft
Structures”, 30 October 1998
3. AFI 91-204, “Safety Investigation and Hazard Reporting”, 30 July 2019
Purpose:
MIL-STD-1530 (Reference 1) establishes the requirement for the classification of aircraft
structural parts/processes and the controls for those critical parts/processes. The
purpose of this Structures Bulletin (SB) is to establish guidance in the classification of
these critical parts during the design phase of a program.
This SB does not apply to USAF landing gear structure since safe-life design concepts
and damage tolerance evaluations are normally used in its design (see 5.1.3.5.2 in
Reference 1).
Discussion:
MIL-STD-1530 (Reference 1) provides the definition of the structural critical parts and are
repeated below for ease of reference:
Normal-controls (NC) part is a non-safety-of-flight structural part where standard
aerospace practices are sufficient in the design, manufacturing, and maintenance
of the part to ensure structural integrity.
Durability-critical (DC) part is a non-safety-of-flight structural part that is judged to
require additional controls beyond those for normal-control parts.
Fracture-critical (FC) part is a safety-of-flight structural part that is not single load
path nor judged to require serialization and traceability.
