Teledyne Technologies Inc. said first-quarter and 2001 earnings will be less than forecast because of declining sales of electronics and aircraft-engine parts, sending its shares down 27%. The Los Angeles-based company said it will increase temporary layoffs by an unspecified amount and cut spending to lower expenses. Profit probably will be 15 cents a share in the quarter and 95 cents in 2001, Teledyne said. Analysts on average were expecting 25 cents for the quarter and $1.21 for 2001, according to First Call/Thomson Financial. A company spokesman said temporary layoffs probably would be less than 100 of the company's 5,700-strong work force. Teledyne, which makes relays used to test computer chips, has been hurt by a slowdown in demand for products such as cellular telephones and computer-networking devices. Many investors were unaware that sales of aircraft-engine parts also slowed, Sidoti & Co. analyst Steve Wortman said. Teledyne shares fell $5.40 to close at $14.30 on the NYSE.