Don't say "Airplane"

[Mike M]

Welding oxygen is used in certain types of welding techniques, either to aid in the production of heat or as an additive to aid in stability of the process. While in use, other contaminants may enter the oxygen cylinder, such as acetylene. When a cylinder must be filled with oxygen, the fill station operator will detect whether there is a presence of acetylene. If there is, the cylinder is cleaned and later filled with oxygen. If the cylinder is labeled for medical oxygen, the cylinder must be evacuated before being refilled.
Aviation breathing oxygen (ABO) is strictly regulated, and neither medical nor industrial grade oxygen can be substituted because of these standards. The CGA’s Grade E is commonly also called aviator’s grade, and this oxygen must also go through additional drying steps before it goes into a cylinder.
Research grade oxygen is 99.999% pure (“five nines,” also called grade 5) and is used in both chemical research facilities and specialty welding applications in the aerospace industry.
Medical oxygen is used for oxygen therapy and hospitals, is designated as a drug and therefore must satisfy FDA requirements for compressed medical gas. One of the requirements is that cylinders containing oxygen must always be completed evacuated to minimize the risk of contamination.

The Airgas facility in Flagstaff, 2004. Saw their servicing facility. One tank of LOX fed a manifold. On the manifold, takeoff fittings labeled "welding", "medical", and "aviator breathing" along with the appropriate warnings, hazmat labels, regulatory gobbledegook. One LOX tank, one manifold. I'll believe what the reference said. I'll also believe what I saw in practice by one of the biggest and most reputable companies in the business, a subsidiary of one of the largest companies in the business worldwide, to meet those standards. Of course, the world has changed a lot since 2004.

[Mike M]

Unless someone gets VERY sloppy with a welder, a socket wrench or screwdriver is not likely to become incorporated into the aircraft structure. Makes it harder for a lawyer to point at it and claim it's the cause of the accident.

So true! But it happens. Once upon a time when I was a little boy in the Navy, an aircraft needed a repair to the tail fairing. When opened up they found a wrench etched with "HC-1 airframes" but the aircraft hadn't been assigned to HC-1 in the previous fifteen years. Hmmmmm

[FlyingRon]

There was a story of someone finding a wrench buried inside the fuselage of a Navion decades later. It was amusing because the A&P who found it was working with the guy who lost it (I was wondering where that thing went).

[Airmutt]

Kinda on the same line.... in the 60’s Howard Hughes bought a couple of Lockheed Jetstars. One of the acceptance pilots left a thermos bottle in the cockpit. HH would not let him open the aircraft and retrieve it. As a kid I can remember my dad lifting me up to peer into the cockpit to see it during an open house event. They were kept in a hangar which Lockheed eventual turned into a secure facility. Never did know what happened to those Jetstars.

[martymayes]

Ironically that don’t say airplane rule doesn’t seem to apply when shopping for tools. Hmmmm...... wonder why???

Just about every tool at Harbor Freight has a tag that says "Not for use on aircraft" Even the transmission jack they sell.

[Snaproll]

The Airgas facility in Flagstaff, 2004. Saw their servicing facility. One tank of LOX fed a manifold. On the manifold, takeoff fittings labeled "welding", "medical", and "aviator breathing" along with the appropriate warnings, hazmat labels, regulatory gobbledegook. One LOX tank, one manifold. I'll believe what the reference said. I'll also believe what I saw in practice by one of the biggest and most reputable companies in the business, a subsidiary of one of the largest companies in the business worldwide, to meet those standards. Of course, the world has changed a lot since 2004.

The manifold described is very common when being fed from a Liquid Oxygen Tank, evaporator, and compressor as the vendor is using 99.999% pure LOX. Each outlet has a check valve thereby they can feed to aviators oxygen, medical, and welding tanks without the issue of contamination. In reality, all tanks are filled with the 99.999% purity oxygen. LOX used to be around 60 cents per gallon delivered.
vr... Don Stits