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The Hercules C-130 get unserviceable often due to various technical issues. This causes the flight to be aborted (ground or air abort) due to avionics, propulsion, airframe or electric problems. I know that the three level of maintenance include 'O' (organizational or 1st level), 'I' (intermediate or 2nd level), and 'D' (depot level). USAF work cards are followed in all these inspections/maintenance.

I was wondering why commercial airliners, which no doubt are flying more than the C-130s, are rarely seen aborting a mission and diverting to a place other than the destination. Is there a different procedure or plan or work package followed by the commercial airliners which make the flight more reliable?

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    $\begingroup$ Welcome to aviation.se. Please refrain from writing in all caps, we are not generating NOTAMs. $\endgroup$ – Federico♦ Mar 8 '18 at 9:51
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    $\begingroup$ Maybe some source would be required to confirm that C-130 is much more unreliable than any other plane. It is produced since 1954 to present, how nobody noticed? $\endgroup$ – h22 Mar 8 '18 at 10:22
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    $\begingroup$ Maintenance regimes are only part of the story. The aircraft design and complexity, age, and of course the type of mission all factor into aircraft reliability. $\endgroup$ – Ben Mar 8 '18 at 10:23
  • $\begingroup$ I would guess that not being shot at makes a difference, too. $\endgroup$ – Jörg W Mittag Mar 8 '18 at 14:26
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As mentioned, factors like a different mission are much more likely to be a reason for any difference in reliability. Military aircraft often fly a harsh mission, the pilots don't fly to extend life, they use max power on every takeoff, fly at a high power setting, and run the engine closer to its temp limit. They aim to get there fast, and the C-130 flies into dirt strips, where the dirt gets ingested into the engines. In comparison, commercial airlines operate with a very close eye on the bottom (financial) line. They take-off derated if they can, and fly with a very simple cruise profile. They do not perform high speed tactical descents that a military C-130 would, into an airport possibly surrounded by hostile forces with air to ground weapons.

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I don't think it makes a lot of sense to try to compare military aircraft (in general) to airliners. There are just too many differences in what's expected of them and how they're used to make a comparison at all meaningful.

Compared to other military aircraft, the C-130 doesn't stick out as doing particularly poorly in terms of mission readiness (nor does it stick out as doing unusually well)1.

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On the other hand, if your standard of comparison is the C-17, then it's absolutely true that the C-130 looks fairly poor in comparison. A difference of roughly 10% in readiness rate might not initially seem particularly terrible. In reality, it's probably more reasonable to think in terms of the number that aren't mission capable at any given time. A C-130 is nearly twice as likely as a C-17 to be down for maintenance at any given time. That's balanced to some degree by the fact that we have a lot more C-130s though.

1. https://www.airforcetimes.com/news/your-air-force/2018/03/05/fewer-planes-are-ready-to-fly-air-force-mission-capable-rates-decline-amid-pilot-crisis/

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  • $\begingroup$ i was going thru the mission capable rate of C-130 H and C-130 J. what is the reason for such low reliability? what all issues are resulting in this low rate $\endgroup$ – ZEESHAN Mar 22 '18 at 4:04
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It is certainly true that military aircraft often operate in harsher conditions than commercial airliners, creating more wear and tear. But they could still be made more reliable. It comes down to how much the operator is willing to pay for a higher reliability, in terms of up front cost and performance.

Commercial airlines are running a business. They pay a lot for their aircraft, and every minute that the airliner isn't moving passengers from A to B is lost revenue. This causes inconvenience for the passengers and expense for the airline. Passengers tend to choose the airline that is cheaper and less likely to leave them delayed. And every dollar spent on maintenance comes out of profit. Similarly, manufacturers are competing to provide more reliable aircraft. They spend a lot of time ensuring their designs will be reliable, and improving designs based on service experience.

The military is in a different situation. Passengers or cargo is not at much risk of choosing a different carrier based on cost or reliability. And for willing to allow lower reliability, the military can trade it for lower upfront costs and higher performance. This means they can carry large cargo, make short takeoffs, climb quickly, operate unpressurized, make steep approaches, land harder on rougher ground, and stop quickly.

Age is another factor. Airlines in the US have average fleet ages of around 10 years (with some outliers on both sides). The active duty fleet of C-130 aircraft has an average age of 25 years. While military airlifters may fly fewer hours, age still factors into maintenance. Components break down over time. Newer planes will have the latest design updates and be less likely to develop issues.

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