Is a drop test always required for a military flight case?

Yes. Lots above 500 take one drop per 500 cases; a first lot takes one.

Is an acceptance quality limit of 1.0 too strict?

Not for air transport: about one defective case per hundred.

Is 48 hours of salt spray enough?

For ordinary sea freight, yes. For long ocean legs, raise it to 96 hours and write that in.

If sampling finds one defect, can we replace just that case?

Not for key items, which reject the lot; ordinary items go by count.

Can a supplier report replace incoming inspection?

No. It reports the supplier process; incoming inspection reports this lot.

Military Flight Case Acceptance Standards: Items and Verdicts

Quick answer: Acceptance of a military flight case runs in two layers: five incoming tests (appearance, dimensions, sealing, drop, salt spray) and a counting sampling plan. A key item failure rejects the lot, and every reading goes into a record kept 36 months.

The Five Incoming Tests for a Military Flight Case
Appearance and Dimensions: Gauges, Points, Tolerances
Sealing and Drop: Two Destructive Checks
Sampling: Lot Size, Sample Size and Acceptance Numbers
Verdicts and the Record Sheet
FAQ

1. The Five Incoming Tests for a Military Flight Case

Incoming inspection of a military flight case answers one question: can this lot enter the warehouse. Five items run look first, measure second: appearance, dimensions, sealing, drop, salt spray. The last three destroy the sample.

Item	Method	Criterion	Sampling
Appearance	Visual, 1000 lux	No crack, no scratch through skin, sink under 0.5 mm	Full
Dimensions	Tape, laser meter	Plus or minus 1.5 mm, diagonal under 2.5 mm	5 per lot
Sealing	Air at 20 kPa, 60 s	Drop under 1 kPa	3 per lot
Drop	1.2 m, 10 drops	No crack, no release, gap under 2 mm	1 per 500
Salt spray	Neutral, 48 h	Rating not below 9	1 per lot

The order cannot be swapped: a cracked shell sent to the sealing rig is a crack being inflated, and an out-of-tolerance case sent to the drop rig lands off its ribs.

2. Appearance and Dimensions: Gauges, Points, Tolerances

Appearance is judged at 1000 lux from 500 mm, with countable criteria: no cracks, no scratch through the skin, sink marks under 0.5 mm, none on the seal face.

Military Flight Case: lid open on a workshop bench awaiting inspection, scratched recessed lid panel, grey foam cutouts with olive pouches, stacked boxes behind

Dimensions are taken at three points: external length, width and height, cavity diagonal, lid-to-body offset. A diagonal spread above 2.5 mm means a twisted body; an offset above 1.0 mm shears the gasket.

Gauges belong in the standard: a 3 m tape outside, a laser meter on the diagonal, a feeler gauge on the offset, checked against a master part.

3. Sealing and Drop: Two Destructive Checks

Sealing uses air rather than water, because it leaves a number. Charge the latched case to 20 kPa through the equalisation valve, hold 60 seconds, pass anything losing under 1 kPa. A failure is checked for a continuous gasket imprint first.

Drop runs from 1.2 m onto concrete: one corner, three edges, six faces, ten drops. No shell crack, no latch release, lid gap no wider than 2 mm.

Salt spray runs 48 hours neutral, rating not below 9, against hardware only. Rusted latches lose half their pull force within six months.

4. Sampling: Lot Size, Sample Size and Acceptance Numbers

Lot release for a military flight case uses counting sampling at general level II, acceptance quality limit 1.0. Sample size follows lot size, not order urgency.

Military Flight Case: closed case lying across a two-wheel hand truck, three metal latches on the face, scuffed walls, empty warehouse shelving

Key items skip the table: sealing takes 3 cases per lot, drop takes 1 per 500; one failure among those four rejects the lot.

Lot size	Code	Sample	Accept	Reject
51 to 90	E	13	0	1
91 to 150	F	20	0	1
151 to 280	G	32	1	2
281 to 500	H	50	1	2
501 to 1200	J	80	2	3

Ordinary items: at or below the acceptance number the lot passes, at or above the rejection number it fails.

5. Verdicts and the Record Sheet

Three verdicts exist: accept, reject, re-inspect after rework. Rework covers appearance and dimensions only; a sealing or drop failure points to a process fault no single repair represents.

Field	Entry rule
Lot number	Match the delivery note
Sample size	Number drawn, never below the table
Test item	One of the five, never merged
Reading	Number plus unit, never pass or normal
Verdict	Accept or reject, one per reading
Inspector, date	Signature and date

Records stay 36 months. Three lots failing the same item means a mould or process problem, not a lot problem; only records show it.

Conclusion

Standards exist so two people reach one verdict: five items with fixed methods and criteria, a sampling table with fixed sample sizes, a record sheet with fixed fields. An argument becomes a lookup, and that is where acceptance for a military flight case rests.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.