AOP-4375
AOP-4375 safety drop test procedures for munitions
Defence test organisations and munitions programme teams running a safety drop test as part of a Safety and Suitability for Service assessment
AOP-4375 is NATO's test procedure for showing a munition stays safe to handle and dispose of after being dropped from the height it could face in service.
- Edition
- A
- Published
- 2024-07
What it is
AOP-4375 is the NATO Allied Ordnance Publication that governs safety drop testing for munitions: whether a munition, dropped onto a hard surface from the maximum height it could plausibly meet during its life cycle, remains safe enough afterward to move away and dispose of. It is not a test of whether the munition still works. Edition A, Version 1 was promulgated in July 2024, and it takes its force from STANAG 4375: the agreement by which NATO nations commit to using it. A nation ratifies that STANAG and implements the AOP domestically, so whether it applies to a given programme is a question of national implementation and a contract or tender, not something the AOP settles on its own.
Where it sits in a wider safety case
A safety drop test under this AOP is one piece of evidence inside a larger process, not a stand-alone requirement. It sits inside the Safety and Suitability for Service (S3) assessment that AOP-15 and the commodity-specific AAS3P standards describe, and it borrows its mechanical test method from AECTP-400 (Method 403 Procedure IV) rather than defining its own. Munition hazard classification work under STANAG 4123 and AASTP-03 is the normal companion activity. The AOP is explicit about what it does not cover: drops with a horizontal velocity component such as a parachute drop, an item falling onto a munition, and munitions jettisoned from aircraft all sit outside it.
What the test actually depends on
The AOP's own drop parameters are not fixed for every munition. They follow from that munition's Life Cycle Environmental Profile, and a National Authority can call for a different height, or an added safety margin, where its own analysis of in-service handling says the standard assumption does not fit. The same National Authority also decides matters like environmental pre-stressing of the test item. That makes AOP-4375 more a procedural framework than a fixed checklist: the test plan and the life-cycle analysis behind it have to be agreed and defensible before a test runs, and its own structure covers test item preparation, the test method, documentation, what has to be observed and recorded, and how the result is judged, without stating one number that applies to every munition.
What evidence it produces
Run properly, a test under this AOP generates test plans, instructions and reports built to AECTP-400's requirements, a specific set of additional observations for each drop, and a video record of the test. Where the same drops are also used to support dangerous goods classification, the results have to satisfy the UN Manual of Tests and Criteria as well, and any test failure has to be reported to the National Authority for that purpose regardless of what the test was primarily run to show.
Who evaluates it
There is no certification body and no accredited scheme in this document. A National Authority reviews the test evidence as part of the munition's S3 assessment, and forms its own judgement about the specific munition rather than certifying an organisation. That is a different mechanism from an audited management-system standard: it is a national safety-assessment process, run against the munition in front of it.
How we help
The physical work under AOP-4375 - preparing the test item, running the drop, and judging what happened on impact - is done by a test organisation, not by software. What a programme needs around that work is a controlled trail: the life-cycle analysis and test plan that justify the parameters a National Authority signed off on, the procedures that define who does what before and during a test, training records for the people involved, and a single place to hold the resulting test reports, observation logs and video evidence so they can be produced when asked for. ComplyTrain is built for exactly that kind of evidence trail, and it also helps track any corrective action a test result raises and keep it linked back to the S3 assessment it supports.
ComplyTrain does not run the drop test, does not set the drop height or other test parameters a National Authority is responsible for, and does not judge whether a munition passed. Those stay engineering and national-authority decisions. In defence work, the standards that apply to a given programme are set by the contract and the customer's quality clause: explore the standards library to see what sits alongside AOP-4375, or talk to us about the evidence trail behind it.
Questions
Is AOP-4375 mandatory?
Only through national implementation. AOP-4375 binds a nation once it has ratified STANAG 4375; it reaches a supplier or test facility once a national safety programme, a contract or a tender invokes it, not automatically.
Does AOP-4375 set the drop height for every munition?
No. It sets the test procedure, but the actual drop height and related parameters for a specific munition come from that munition's own Life Cycle Environmental Profile and from the National Authority's judgement, not from a single figure fixed in the AOP.
Can a company be certified to AOP-4375?
No. The document names no certification scheme. A drop test's evidence feeds a National Authority's Safety and Suitability for Service assessment of the munition, which is a national safety judgement, not a certificate issued to an organisation.
How does AOP-4375 relate to AOP-15?
AOP-15 sets out the Safety and Suitability for Service assessment framework for non-nuclear munitions; a safety drop test under AOP-4375 is one piece of evidence that assessment can draw on, not a separate requirement running alongside it.