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Comment by FigBug | Hacker News Reader

There were six shuttles and had 25, 28, 10, 39, 33 & 0 missions each for a total of 135 missions and killed 14 astronauts. Not that impressive a record for something that was originally intended to do 55 launches a year.

Something I find more impressive is the B52 Bomber, first flew in 1952, finished production in 1962, expected to be in service until 2040. Will be in service for almost 100 years.

If like an aircraft, you were doing 1 hour of maintenance for every 10 - 20 hours driving, I'm sure your car would be more reliable.

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For military aircraft, there are far more hours of maintenance than flying time. It's a factor of 10-20 in the other direction.

Indeed.

I originally enlisted in the Navy as an Aviation Structural Mechanic (AM), and my first command was an F-14 squadron where I was assigned to airframes. On average, we scheduled 40 man hours for each flight hour (sometimes as high as 60). The F/A-18's that eventually replaced the Tomcats took about half that, but for most aircraft you're looking at 10 MMH/FH, at least, for mx alone.

That said, not all aircraft are created equal, and not all those Tomcats required all 40 scheduled man hours. Maintenance manning, at least in the Navy, is largely determined by man hours. So it isn't uncommon for commands to log as many hours as they can to keep billets, and possibly get a few additional ones. Billets are taken away if you show you can operate at fewer man hours.

I actually looked up the B-52 schedule and from what I could tell its maintenance and duty schedules aren't too out of line from recommended maintenance for a privately owned automobile:

https://plus.google.com/u/0/104092656004159577193/posts/PfZc...

The Boeing B-52 Stratofortress was introduced in 1952. Its mission is presently projected through 2044.[1] That's a ninety-two year mission.

There were 744 built, unit costs range from $9.28 million (1962) to $53.4 million (1988). The most recent new production was 1963, over a half century ago. Effectively the planes are rebuilt periodically, though some original components may remain (I'm not fully up on my B-52 maintenance procedures and schedules).

"Flyaway cost": $9.29m, in 1955 dollars, $82.53 in 2014 dollars)

Present maintenance costs: $10,406/hr.

That is equivalent to the purchase price of the aircraft every 8,000 flight hours.

AAA publishes a "cost of ownership" report for automobiles which assumes 15,000 miles of travel and an average of $0.05/mi maintenance, or $750/year.[2] This suggests that a B-52 level of maintenance is at least twice the going cost of automobile maintenance. But not hugely out of line given relative capital costs.

GlobalSecurity.org claims B-52 total service life being 32,500 - 37,500 flying hours.[3] Over the 92 year life of the program, that corresponds to a duty cycle of roughly 4.6%, vs. 5.7% for the automobile referenced above. It also gives us an annual maintenance cost per B-52 of $4.2 million -- or 5% of the total purchase cost. Over the 92 year life of the aircraft, that's equivalent to purchasing 4.7 new planes.

(Taken from a longer response to an allegation about failure to incorporate demand-side depreciation in GDP, largely deconstructed, demolished, and dismissed here.)

Also, incidentally, I dropped you an email concerning your "Internet with a Human Face" blog posting, seen that by chance?

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Notes:

1. http://www.gizmag.com/b52-upgrade/20098/

2. http://www.colorado.aaa.com/auto/fuel-guide/driving-costs-fo...

3. http://www.globalsecurity.org/wmd/systems/b-52-life.htm

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