July 22 (Reuters) - Lockheed Martin ( LMT ) reported on Tuesday

that its second-quarter profit plunged by about 80%, after the

U.S. defense giant recorded pre-tax losses of $1.6 billion,

mainly linked to a classified program within its Aeronautics

segment.

The company's shares fell 8% in premarket trading.

Its net income dropped to $342 million, or $1.46 per share,

compared with $1.64 billion, or $6.85 per share, a year earlier

Lockheed said the charge stemmed from difficulties with

a classified program in its Aeronautics business and to certain

international helicopter programs in its Sikorsky unit.