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Archive for October, 2018

Another consequence of very high flight to maintenance ratios in aircraft – vulnerability to disasters

Posted by altandmain on October 15, 2018

This article discusses how flight to maintenance ratios can leave air forces exposed to the unexpected, including natural disasters.

A high flight to maintenance ratio is one of the big issues in fighter aircraft that are complex. It is often an issue that does not go acknowledged during the procurement stage of military spending, but has immense consequences. Lower is better in this case, because it means less maintenance is needed per hour of flight.

Flight to maintenance ratio, roughly means that for every hour of flight, how many man maintenance hours does one need on average to keep the aircraft operational? A high flight to maintenance ratio means that more man hours are needed for every hour of flight.

The B2 stealth bomber, for example has the worst flight to maintenance ratio, and as a result seldom flies.

Hurricanes and other losses

Recently, a hurricane struck the United States. What occurred is that the hurricane, Hurricane Michael, took a sudden turn that was not expected and changed course towards the Florida Panhandle, where Tyndall Air Base is located. Tyndall Air Force Base is a major US Air Force base, where many F-22 stealth fighters are stationed.

There were 55 F-22 aircraft stationed there, but only 33 were moved out and the status of the remaining 22 are not known. It would seem that some were destroyed by the hurricane.

It is likely based on the comments that the USAF could simply not evacuate them quickly enough.

Air Force officials have not disclosed the whereabouts of the remaining 22 planes, other than to say that a number of aircraft were left at the base because of maintenance or safety reasons.

An Air Force spokeswoman, Maj. Malinda Singleton, would not confirm that any of the aircraft left behind were F-22s.

But photos and video from the wreckage of the base showed the distinctive contours of the F-22’s squared tail fins and angled vertical stabilizers amid a jumble of rubble in the base’s largest building, Hangar 5. Another photo shows the distinctive jet in a smaller hangar that had its doors and a wall ripped off by wind.

All of the hangars at the base were damaged, Major Singleton said Friday. “We anticipate the aircraft parked inside may be damaged as well,” she said, “but we won’t know the extent until our crews can safely enter those hangars and make an assessment.”

It is likely based on the comments that the USAF could simply not evacuate them quickly enough. The extent of the damage, if you read the full article, is not yet known, but appears to be extremely extensive.

The reason why aircraft like the F-22 are going to be affected by this is because stealth aircraft have a set of unique characteristics that make them vulnerable:

  1. A very high flight to maintenance ratio means that they simply cannot take off quickly enough. They are down for maintenance when they need to move most urgently.
  2. There are fewer of them (since there are less than 200 F-22s due to the costs to manufacture them and because the program was terminated early), so any losses will be a larger percentage of total fleet losses.
  3. Where they can evacuate to is limited. Stealth aircraft like the F-22 or B2 need special climate controlled hangars and have a lengthy supply chain.
  4. The sheer complexity means that there will be unexpected downtown of these aircraft. From the article below:

The high-tech F-22 is notoriously finicky and not always flight-worthy. An Air Force report this year found that on average, only about 49 percent of F-22s were mission ready at any given time — the lowest rate of any fighter in the Air Force. The total value of the 22 fighters that may remain at Tyndall is about $7.5 billion.

This is inherently exposed in not just a war against a competent enemy, but also in peacetime against natural disasters.

A brutal reality of this world is that disasters that occur suddenly will happen. Whether they be hurricane/typhoons, tornadoes, earthquakes, fires, or any other disaster, a smaller fleet with a high flight to maintenance ratio means that the entire fleet of aircraft is far more vulnerable to being caught by surprise by these events.

The F-35 would also be affected

The F-35 JSF is significant in that it will be replacing the majority of aircraft in not just the USAF fleet, but also several NATO allies.

The F-35 also suffers from a high flight to maintenance ratio.

Four years into their operational career, F-35 fighters are expected to require between 41.75 and 50.1 maintenance man-hours (MMH) per flight hours, or about three times as many as most fighter aircraft currently operated by Western air forces.

Considering both the F-35 and F-22 are in this situation, this will leave the fleets of Western air forces far more vulnerable, not just to enemies in a war, but also to natural disasters and other unexpected events.

What would be the solution?

The solution is to procure cheaper aircraft (so that more aircraft can be procured and losses would be a small percentage of the fleet). These aircraft would be more widely dispersed, so that they are harder to destroy, either by an enemy, or in this case by a natural disaster.

Picard’s FLX proposals are a good step forward to protecting the Western air forces against losses like this one.

The existing aircraft would be retired. This is not without historical precedent. The F-14 was retired in part due to its unfavorable flight to maintenance ratio.

The decision to incorporate the Super Hornet and decommission the F-14 is mainly due to high amount of maintenance required to keep the Tomcats operational. On average, an F-14 requires nearly 50 maintenance hours for every flight hour, while the Super Hornet requires five to 10 maintenance hours for every flight hour.

Not only does a more complex aircraft mean fewer aircraft due to the expensive unit costs, but it also means fewer sorties per aircraft because they will be down for maintenance. This is on top of the greater vulnerability to natural disasters.

A historical perspective

Natural disasters, in the history of war, have played a key role in swinging the outcomes of many wars in the past. It would be extremely inadvisable to think that modern armies are immune to the effects of unexpected natural disasters and other weather events.

Furthermore, if we consider the effects of a natural disaster on these aircraft, what could the effects of a surprise attack be from a competent enemy? With so few aircraft concentrated in a handful of bases, and with such a high flight to maintenance ratio, the losses could be quite bad indeed. These aircraft would be in known locations on the ground. Forget for a moment about being radar stealthy in the air and worry about being exposed on the ground. Prudence would demand that we reduce our vulnerability to such events.

In a way, the OODA loop is much slower with these aircraft. Since it takes so long to maintain each aircraft, the ability for an air for with a large percentage of its total aircraft with high flight to maintenance ratios to react to a changing battlefield. It would take more time for example, for intelligence to be relayed and then a sortie generated in response to that intelligence. There are fewer aircraft, concentrated in a handful of locations, and they need more time before going to a sortie to prepare.

Clearly the solution is to procure more aircraft that are less complex, cheaper, and easier to maintain. This will not only mean fewer losses due to unexpected events, but also a much faster OODA loop.

This is an extremely costly lesson to learn, but fortunately one that was learned in peacetime and not in a war.

On a final note, I wish the best of luck to everyone affected by Hurricane Michael.

 

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