Originally Posted by
clark y
WRT the object, I'd think flat blade screws haven't been used in a while in an aviation application. (Could be wrong). If it is not a fire bottle, what is it?
I have removed and replaced many aircraft fire bottles in my career as an AME, and though the item in the photograph bears a superficial resemblance to one, I really don't think that is what it is.
Every fire bottle I have ever seen has a pressure gauge built into the side to indicate that the unit does indeed contain a full charge of extinguishing agent. No sign of such.
More importantly, an engine or APU bottle will have at least one, (and more often two), threaded female couplers for the large-diameter piping that conducts the agent to the appropriate location when the bottle is discharged - either to a dispersal nozzle within the engine cowl, or within the APU enclosure as the case may be. There is no sign of anything like that on the item in the photograph.
Also, the item in the photos appears to be made if a thicker gauge metal than is typical of aircraft fire bottles. The flush-mounted threaded plug in one side is also unusual.
The silver cylindrical device mounted to the side of the sphere bears a superficial resemblance to the electrical firing squib used on an aircraft extinguisher, but again, there is no sign of the threaded female coupling for the discharge line, which normally connects right below the squib.
And, as you point out, the use of slotted mounting screws is not often seen in aircraft. The fire bottles I am familiar with are all mounted to the aircraft structure with bolts.
Having said this, I have to point out that my experience with aircraft extinguishers is specifically on small to mid-size business jet aircraft. I have never seen or worked with the type of extinguishers that would typically be used on an airliner or cargo aircraft for cargo bay fire suppression. Perhaps that kind of extinguisher would look more like what is displayed in the photo.
Two things in the photos that DO suggest this item is from an aircraft, are the inked manufacturer's inspection stamps on the cylindrical device on the side, and the use of twisted lockwire to secure the end cap on the cylinder. There appear to be two wires protruding from the end of the cylinder, and firing squibs usually use a two-wire connection.