Status: concept design. This article describes an internal engineering concept dossier (FPRS-CD-001, Rev A). Nothing described here has been built, tested, qualified or certified. Every figure is a design target, not a measured result. We are publishing the reasoning, not a product.

The problem is not comfort. It is cognition.

A long-duration fast-jet sortie can run 8 to 10 hours. That comfortably exceeds bladder capacity. The near-universal workaround among aircrew is voluntary dehydration - deliberately under-drinking before and during a flight.

That trade is a bad one. Dehydration degrades cognitive performance and reaction time, increases susceptibility to G-induced loss of consciousness, and raises the risk of urinary tract infection. The pilot is trading physiological reserve for the absence of a bathroom.

Legacy "piddle-pack" absorbent bags were designed around male anatomy. Under a harness, in a confined cockpit, at sustained G, they are impractical for female aircrew. The result is that a solved problem for one group remains unsolved for another.

Design intent

The concept is a reusable, aircraft-mounted urine collection and transfer system that lets the pilot void without breaking a seated, strapped-in posture. The design envelope assumed for analysis is +9/-3 Gz, with high vibration, low ambient pressure and any aircraft attitude including inverted. That envelope is an assumption requiring validation, not a qualified figure.

How it works

The pilot wears only a soft, single-use collector. Every expensive component - pump, motor, battery, controller, storage bag holder - is fitted inside the aircraft and reused between sorties.

A moisture sensor in the collector signals the controller to start a small pump. The pump moves urine through a tube into a sealed bag containing a gelling agent, which locks the liquid into a solid gel so it cannot slosh or spill under high-G manoeuvring or inverted flight.

Four decisions worth explaining

Only the collector is disposable. Consumable cost per sortie stays low because the costly parts never leave the aircraft.
The pump never touches urine. Fluid contacts only the inside of a replaceable tube. The pump head stays clean, which makes servicing a tube swap rather than a decontamination procedure.
No wet pad against skin. Urine is pumped away and gelled rather than absorbed and held against the body - the difference between a hygiene problem and a hygiene solution.
Two connectors, two jobs. One locks firmly for routine use. A second quick-release separates instantly on ejection and seals both ends so nothing leaks. Ejection is the case that governs the design.

What we are not claiming

No test results. No qualification status. No airworthiness or certification claim. No approval from any authority. The dossier's own approval page records no signatures, and the document is marked "not for manufacture or flight."

We are publishing this because the reasoning is useful and because the underlying problem is under-addressed. If it becomes a prototype, we will publish the test data - including the parts that fail.