Performance of Key MX Device Is Challenged : Unit’s Failure Rate Appears Higher Than Air Force Claims
A key part of the MX missile guidance system has experienced a 58% failure rate in deployed missiles at a Wyoming base over the past 10 months, even though the Air Force says the system is exceeding its reliability requirements, according to congressional investigators who have obtained MX failure reports.
The guidance device, built by Northrop, has experienced 28 failures in the 48 systems delivered since last October, according to staff members of an investigations subcommittee for the House Energy and Commerce Committee.
Their interpretation of the MX documents appears to contradict Air Force statements that say the reliability of the system, called an “inertial measurement unit,” is twice as good as had been predicted for this point in the program.
Northrop, a Los Angeles-based aerospace company, has come under heavy scrutiny in the MX program and remains under two congressional investigations, a grand jury probe in Los Angeles and a series of Air Force actions.
More Funds Withheld
A company spokesman said Sunday that the Air Force has increased to $108 million the amount of contract payments it is withholding from Northrop because of late deliveries of IMUs. Northrop has been four months behind schedule in deliveries, leaving about one-third of the 21 MX missiles in silos without guidance systems as of the end of June.
Air Force officials, however, have defended the reliability of the IMUs, citing their own failure figures. In a letter written to The Times last month, Air Force Gen. Lawrence Skantze, who has since retired, took sharp exception to allegations by the House committee that the IMU reliability was not as good as he had indicated.
Skantze said that there had been only nine IMU failures that could be attributed to the Northrop electronics division in Hawthorne, the prime contractor for the IMU. That figure apparently does not include any possible failures in equipment supplied as “government-furnished equipment” to the Northrop electronics division by the Northrop precision products division and Honeywell.
An Air Force spokesman said Sunday that he could not explain the discrepancy in the figures.
The Northrop spokesman said that, based on performance records, there have been 22 IMU failures through Aug. 7, a longer time period than considered by congressional investigators, resulting in a failure rate 18% better than expected by the Air Force.
But the documents obtained by the House committee, which are called Northrop “IMU failure summaries,” show that there have been 28 failures since the MX missiles were made operational last October, a member of the committee staff said.
In addition, the committee staffer said the way the Air Force tallies the reliability of the IMU leaves gaping loopholes for the system to repeatedly fail without hurting the results. In many cases, failures are “scored” in a way that does not affect reported reliability, he said.
The summary documents include the date, a serial number and a description and analysis of each failure dating back to the beginning of the program. The incidents, among other things, included failed pumps and electronic problems.
The summaries also show 125 IMU failures since Oct. 31, 1982, when the company was early in its development efforts. Such early failures are usually expected in a development program and are not an indication of the system’s current reliability.
The IMU is a basketball-sized device that contains 19,401 parts, which all float inside a fluid-filled chamber in the missile nose. Temperatures inside the spheres, which cost about $5 million each, are set to within one-hundredth of a degree.
The House committee also has obtained a series of Northrop “field return” reports. Those reports were submitted to the committee by Herbert Hafif, a Claremont attorney who is representing more than half a dozen Northrop employees who are suing the company on behalf of the U.S. government.
The field return reports show that there were 22 failures alone of so-called hybrid circuits, which are high-density electronic devices about the size of a matchbox. The hybrid circuits are the subject of one of the lawsuits pressed by Hafif.
But Northrop said it has found only one hybrid failure in 19.5 million hours of operation. The Northrop spokesman pointed out that the company was counting only failures that were directly attributable to a hybrid circuit and only failures that occurred during operational alert status.
The Northrop spokesman asserted that the only valid criteria for judging the IMU is how it performs once it is put on so-called alert status inside a missile silo. Once on alert status, the IMU runs constantly, ready for a launch within a moment’s notice.
A staff member of the House Energy and Commerce’s subcommittee on oversight and investigations said the panel is expected to call a hearing on the MX this fall.
