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The Navy's version of the 53 has a crash rate 3x higher than other helicopters. Maintenance debt killed two of my classmates. https://pilotonline.com/news/mili

The Navy's version of the 53 has a crash rate 3x higher than other helicopters. Maintenance debt killed two of my classmates. https://pilotonline.com/news/military/local/distress-signal-the-human-cost-of-the-navy-s-most/article_060a4418-c412-56c4-b731-da48c25f5d73.html https://pilotonline.com/news/military/local/distress-signal-...

le-mark 9y ago
A worn-out fuel line had been rubbing silently against a bundle of old electrical wires near the front of the cabin – a problem that had gone undetected for years. The same mechanical defect existed inside every Sea Dragon in the fleet, though nobody knew it. Over nearly three decades, the Navy had never required anyone to regularly inspect Sea Dragon wires or fuel lines for damage. Calling this particular problem maintenance debt is a bit disingenuous. PMCS/PMI could have been performed perfectly for decades and not caught this problem. Peculiar dichotomy in this story; the conflation of design flaw and lack of spare parts and improper maintenance.
- dsr_ 9y ago
  The US Navy seems to have lost the culture of maintenance and seaworthiness that they were famous for over the previous half-century.
  - deleted 9y ago
    [deleted]
  - DinkMeeker 9y ago
    This was posted here a few months ago. The article indicated that a change/reduction in training starting in 2003, mainly for cost savings, was coming home to roost. I wonder if similar things are going on in the maintenance area. https://www.militarytimes.com/news/your-navy/2017/08/27/navy-swos-a-culture-in-crisis/ https://www.militarytimes.com/news/your-navy/2017/08/27/navy... https://news.ycombinator.com/item?id=15118141 https://news.ycombinator.com/item?id=15118141
- rbanffy 9y ago
  We shouldn't underestimate what we don't know about building machines. Maintenance should accommodate time to check for wear on parts we don't expect to, to check things that are different from what we expect them to be. The problem was there for decades and one inspection in one unit over that period would probably have evidenced the issue and added one more item for the maintenance checklists. It's not like the manufacturer can't schedule a full disassembly of a unit 10 years into its lifetime. Car magazines do it.
  - dmoy 9y ago
    > It's not like the manufacturer can't schedule a full disassembly of a unit 10 years into its lifetime Wait hang on, I was under the impression that a D check (?) did exactly this, every 6-7 years. This is second hand knowledge from a pilot buddy so maybe I'm forgetting something. Also it's on the civvy side of things, maybe the military does stuff differently? If it's as simple as the military has shittier maintenance checks, then that's a solvable problem. Edit: ok looked it up, it is a civilian vs military thing.
  - geezerjay 9y ago
    > Maintenance should accommodate time to check for wear on parts we don't expect to How much time do you spend performing exhaustive checks for problems that don't exist?
    - colechristensen 9y ago
      You should. You absolutely should spend time looking for things you expect not to find, because sometimes you will be wrong. When you're maintaining an aircraft, a nuclear plant, or anything sufficiently complex or life critical, you should spend a certain amount of time looking for ghosts. You _will_ find them. Your model of an engineered system should include a finite rate of unknown bugs.
    - rbanffy 9y ago
      Very little. In this case, a single inspection (assuming all units were affected) over a period of 20 years would have prevented losses that more than compensate the effort of the added scrutiny. Also, I like to be the first to know I'm wrong. If I make 100 aircraft and dedicate one to disassembly for study after a quarter of its estimated life, I'll be a .75% investment on better understanding my product. If De Havilland had done that, the stress on the square windows of the Comet would have been discovered before they started falling from the skies and we'd all be flying more beautiful planes. I was shocked when I found out that, in more than 100 flights, nobody inspected the underside or the leading edges of the shuttle in orbit to check for damage incurred on lift off. They were pretty sure the only dangerous part of the flight was the re-entry. You say a problem does not exist. You may have good reason to think it doesn't, and, yet, people die because it does.
- Arnt 9y ago
  WTF? I thought aircraft maintenance stipulated that all parts have to be inspected, some often, others seldom, but none never.
  - foldr 9y ago
    A 747-400 has 6 million parts (according to Google). Good luck inspecting all of those.
    - icebraining 9y ago
      On each plane it would not be reasonable, but on a few planes it could be done, and would detect defects like the one described above.
      - Arnt 9y ago
        Aircraft procedures aren't reasonable. Go and read an accident post-mortem sometime, they're gorgeous. They describe debugging with all the dials turned to eleven. Inspirational.
        Parcissons 9y ago
        If at least there where crawlspaces for inspection robots planned into the design.
      - colechristensen 9y ago
        The reasons planes are so safe is because there are several "unreasonable" things about designing and maintaining aircraft that most engineers would think somewhere between unnecessary and ridiculous. A lot can be learned from aerospace engineering and the systems engineering used to design air and space vehicles.
        tyingq 9y ago
        Also, a fair amount of the safety of civilian aircraft is because the aircraft owners don't get to skip critical processes, maintenance, etc. They have to answer to regulatory agencies, inspections, etc. The US military polices itself, so important things can be made optional. They don't have to answer to the FAA on maintenance issues, for example.
- justicezyx 9y ago
  Another statement of treating maintenance & do nothing until it's broken being equivalent. That is disingenuous.
rbanffy 9y ago
I'm sorry to hear that. Aircraft maintenance is the kind of stuff where you really don't want to cut corners. :-(

le-mark 9y ago

A worn-out fuel line had been rubbing silently against a bundle of old electrical wires near the front of the cabin – a problem that had gone undetected for years. The same mechanical defect existed inside every Sea Dragon in the fleet, though nobody knew it. Over nearly three decades, the Navy had never required anyone to regularly inspect Sea Dragon wires or fuel lines for damage. Calling this particular problem maintenance debt is a bit disingenuous. PMCS/PMI could have been performed perfectly for decades and not caught this problem. Peculiar dichotomy in this story; the conflation of design flaw and lack of spare parts and improper maintenance.

dsr_ 9y ago
The US Navy seems to have lost the culture of maintenance and seaworthiness that they were famous for over the previous half-century.
- deleted 9y ago
  [deleted]
- DinkMeeker 9y ago
  This was posted here a few months ago. The article indicated that a change/reduction in training starting in 2003, mainly for cost savings, was coming home to roost. I wonder if similar things are going on in the maintenance area. https://www.militarytimes.com/news/your-navy/2017/08/27/navy-swos-a-culture-in-crisis/ https://www.militarytimes.com/news/your-navy/2017/08/27/navy... https://news.ycombinator.com/item?id=15118141 https://news.ycombinator.com/item?id=15118141
rbanffy 9y ago
We shouldn't underestimate what we don't know about building machines. Maintenance should accommodate time to check for wear on parts we don't expect to, to check things that are different from what we expect them to be. The problem was there for decades and one inspection in one unit over that period would probably have evidenced the issue and added one more item for the maintenance checklists. It's not like the manufacturer can't schedule a full disassembly of a unit 10 years into its lifetime. Car magazines do it.
- dmoy 9y ago
  > It's not like the manufacturer can't schedule a full disassembly of a unit 10 years into its lifetime Wait hang on, I was under the impression that a D check (?) did exactly this, every 6-7 years. This is second hand knowledge from a pilot buddy so maybe I'm forgetting something. Also it's on the civvy side of things, maybe the military does stuff differently? If it's as simple as the military has shittier maintenance checks, then that's a solvable problem. Edit: ok looked it up, it is a civilian vs military thing.
- geezerjay 9y ago
  > Maintenance should accommodate time to check for wear on parts we don't expect to How much time do you spend performing exhaustive checks for problems that don't exist?
  - colechristensen 9y ago
    You should. You absolutely should spend time looking for things you expect not to find, because sometimes you will be wrong. When you're maintaining an aircraft, a nuclear plant, or anything sufficiently complex or life critical, you should spend a certain amount of time looking for ghosts. You _will_ find them. Your model of an engineered system should include a finite rate of unknown bugs.
  - rbanffy 9y ago
    Very little. In this case, a single inspection (assuming all units were affected) over a period of 20 years would have prevented losses that more than compensate the effort of the added scrutiny. Also, I like to be the first to know I'm wrong. If I make 100 aircraft and dedicate one to disassembly for study after a quarter of its estimated life, I'll be a .75% investment on better understanding my product. If De Havilland had done that, the stress on the square windows of the Comet would have been discovered before they started falling from the skies and we'd all be flying more beautiful planes. I was shocked when I found out that, in more than 100 flights, nobody inspected the underside or the leading edges of the shuttle in orbit to check for damage incurred on lift off. They were pretty sure the only dangerous part of the flight was the re-entry. You say a problem does not exist. You may have good reason to think it doesn't, and, yet, people die because it does.
Arnt 9y ago
WTF? I thought aircraft maintenance stipulated that all parts have to be inspected, some often, others seldom, but none never.
- foldr 9y ago
  A 747-400 has 6 million parts (according to Google). Good luck inspecting all of those.
  - icebraining 9y ago
    On each plane it would not be reasonable, but on a few planes it could be done, and would detect defects like the one described above.
    - Arnt 9y ago
      Aircraft procedures aren't reasonable. Go and read an accident post-mortem sometime, they're gorgeous. They describe debugging with all the dials turned to eleven. Inspirational.
      - Parcissons 9y ago
        If at least there where crawlspaces for inspection robots planned into the design.
    - colechristensen 9y ago
      The reasons planes are so safe is because there are several "unreasonable" things about designing and maintaining aircraft that most engineers would think somewhere between unnecessary and ridiculous. A lot can be learned from aerospace engineering and the systems engineering used to design air and space vehicles.
      - tyingq 9y ago
        Also, a fair amount of the safety of civilian aircraft is because the aircraft owners don't get to skip critical processes, maintenance, etc. They have to answer to regulatory agencies, inspections, etc. The US military polices itself, so important things can be made optional. They don't have to answer to the FAA on maintenance issues, for example.
justicezyx 9y ago
Another statement of treating maintenance & do nothing until it's broken being equivalent. That is disingenuous.

rbanffy 9y ago

I'm sorry to hear that. Aircraft maintenance is the kind of stuff where you really don't want to cut corners. :-(