Military Aviation In A 'Death Spiral'?

The Marines grounded virtually their entire fleet of Harrier Jump Jets Wednesday after determining that a crash last month was caused by a defective main engine bearing.

CBS News National Security Correspondent David Martin reports it’s the 27th time in the past eight years that the vertical take off and landing plane has been grounded.

Yet the Marines plan to keep flying the Harrier until 2015, as the age of military aircraft continues to climb.

The 31-year-old CH-46 chopper, one of which crashed earlier this year in the Pacific, is an extreme example but the average Navy aircraft is now 17 years old, the oldest ever.

"The average age of most fighters in the Navy, Marine Corps and the Air Force is only a little bit higher today than it was 10 years ago at the end of the Cold War, but over the next five to 10 years, that age is going to increase a lot," says defense budget analyst Steven Kosiak.

The Pentagon's planes are getting older for one simple reason: It is not buying new ones fast enough. An d aging aircraft mean more groundings.

Last year Army aircraft were grounded 18 times. So far this year there have been 31 grounds. Aging aircraft also cost more operate. A brand new F-18 costs $3,000 an hour. a much older F-14 costs $7,500 an hour.

The more money spent on aging aircraft, the less money there is to buy new aircraft, which is why one senior military officer told CBS News: military aviation is in a death spiral.