51.   But that is not an uncommon situation on long-range commercial aircraft, and none have spontaneously exploded before.

52.   But the authorities were less certain of the market for commercial aircraft parts.

53.   But sales of commercial aircraft have been weak.

54.   But the surge in orders was concentrated in commercial aircraft and military hardware and was not seen as evidence of a pickup in economic growth.

55.   By comparison, the commercial aircraft side of McDonnell Douglas does appear bleak.

56.   By contrast, federal law requires the NTSB to investigate any crash of a commercial aircraft or a private plane involving a death.

57.   By the end of next year, all commercial aircraft are to be equipped with quieter engines, according to a Federal Aviation Authority mandate.

58.   Commercial aircraft orders, for instance, are expected to be a source of strength in the months and years ahead.

59.   Commercial aircraft manufacturing remains a long-term source of strength for the U.S. economy, with Seattle-based Boeing Co. reporting strong orders from overseas.

60.   Commercial aircraft posted a modest gain in July, while orders for defense capital goods declined last month.