You Can’t Get There From Here: Aviation Version

“Where’s the access for the oil drain?”

“Down there. You have to reach past the engine mount, around the back of the supercharger, don’t hit the whatsis, and don’t forget to cut off the safety wire before you try to remove the drain plug. Hanging upside-down helps.”

Except that it’s hard to remember which is right and left when you are half-inverted on the work platform, trying to get to everything while the oil is still warm enough to drain quickly. I really, really disliked the designer who put that thing there.

Oh, and you have to replace the safety wire, which has to go around the plug in a certain way, and be twisted in a certain direction. If you don’t twist the wire tail and bend it so that the end is smooth and blunt, the Crew Chief or next person to work in that area will have WORDS with you. Trusssssst me on this.

I think every airplane and almost every other type of vehicle has one of those things – something you can’t get to easily, or quickly, or that is in a compartment so tightly crammed with expensive and fragile stuff that you are afraid to breathe and more afraid of dropping a hand tool or the gizmo you are trying to troubleshoot/repair/replace. Hellholes are found on all large aircraft, and someone always has to put the battery waaaaaay back in the tail-cone for weight-and-balance purposes. Unless the battery is just in a place that requires removing part of the interior of the plane to get to. Not an easy part, either.

Merlin engines and other in-line designs are infamous, because the designers made as tight a package as possible in order to squeeze everything into a very streamlined design. Trying to get to the starter, or oil drain, or certain other accessories takes slender hands, long arms, and bones like Plastic Man or Gumby. I once looked at a Japanese engine that appeared to have been draped with spaghetti or linguini. All the wires for the spark plugs, all running down the outside of the engine, and getting in the way of, well, finding anything else.

Electronics bays are notorious. Many jets and some turboprops put the guts of the electronic stuff, back in the pre-solid-state days, or when the plane has a radar unit on-board, up front in the nose near the oxygen tanks*. You cannot get to this bay from the cockpit. You have a separate hatch that opens into a dark, cramped, and either hotter than the blazes or colder than a well digger’s hip pocket space that is about as wide as most men’s shoulders. OK, not that cozy, but it feels like when you are trying to do any work in there that requires more than “remove box, slide in new box, close hatch.” Granted, airline-sized planes do have more room, but it’s still dark, and too warm or too cold, and when you drop things, they fall farther. I can pretty much guarantee that the more expensive the [thing], the louder it sounds when it hits the cement, no matter the size of the thing or how many steps on the ladder it hits on the way down.

I have had the privilege of squeezing myself into electronics bays, tail cones, wing roots, and aft fuselages of a number of aircraft. It was fun, and were I still that limber, I’d do it again. But I’d wear much better ear protection.

*In some biz-jets, the emergency oxygen bottles are in the nose. As you pre-flight the plane, you check the bottles, open the valves, and remove a long red “remove before flight” streamer that flaps outside the O2 compartment like a tongue. If the plane is taxiing “with its tongue out,” you’d better park, shut down, get out, and turn on your emergency O2 system. There’s some suspicion about a certain biz-jet crash and the bottles getting overlooked during preflight. Nothing is proven, though, but the super-long crimson streamer stems from that time.

15 thoughts on “You Can’t Get There From Here: Aviation Version

  1. There’s few places to put the emergency oxygen bottles where one hazard or another won’t happen. Electronics might be the lesser of the evils. Wait for the design “genius” who wants to put them by the internal fuel tank, and hopefully hits a lot of steps on the way out.

    I’m at the point where robotic assembly means I can’t get hands or a hand into places for maintenance, without a detailed list of what comes off and in what order, and the special gizmo for their fasteners. This might make manufacturing cheaper, but makes maintainability awful.

  2. I’ve heard people say that the designers of complex machinery should be required to work on/repair such machinery. 👿

    • There is an interchange around here where I tend to say, the designers of it should be required to drive one segment of it. At night. In the snow.

      • The fabulous and ‘Familiar’ Off-Ramp of Doom comes to mind. I know a few of those interchanges, heartily agree.

        • Virtually every interchange on I84 in CT is an ‘interchange by merge and weave’. These are very effective capacity limiters and traffic jam generators, with 35 to 45 minute backups near Danbury and through Hartford.

  3. Ah yes, the ‘fun’ of aviation maintenance… And radials were always a ‘special’ PITA, due to oil being everywhere… Especially if it was a problem with the BACK row of pistons… Which is why I was glad I trained as a metalsmith!

  4. In college I owned a Ford Maverick (basically a sporty fast-back body on a Falcon platform). As I was poor at the time, did I mention I was in collage, I did all of the maintenance and repair work myself. Under the dash was a particularly difficult space to work on, laying on the seat upside down, feet hanging over the seat back, working by feel, and sharp edges of sheet metal everywhere. One memorable chore was when I had to replace the heater hoses. Simple chore right? unclamp the hoses at the water pump, unclamp them from the firewall connections, replace and re clamp. Wrong grasshopper. Instead of putting 3 inches of hard tubing through the firewall Ford in it’s infinite wisdom stubbed the hard tubbing connection 1/2 inch from the heater core inside the cabin. During those days I often asked G_d to ensure that the guy that designed that area be forced to spend at least sometime in purgatory working on that abomination.

    • TINS: A certain engine manufacturer no longer allows mechanics (field type) to meet the designers of the small turbine engines after a mechanic slugged the man who put a certain accessory in a certain location on a very popular and very common turbine engine. Heard the story from a guy who was in that tour group. He was a mechanic, and sounded somewhat less-than-upset about the designer getting punched. He also worked on that type of engine. [details omitted to protect the author]

  5. Wait, there are airplanes that don’t have radars in them? And you sometimes have electronics designed by people who have seen an airplane, much less understand what the maintenance would be like?

    Are you sure that is legal?

    I thought OSHA forbid design engineers from having any knowledge of or experience with the circumstances under which the design might be maintained.

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