The U.S. Air Force is scrapping a troubled $1 billion, seven-year effort to overhaul and modernize its management of logistics — and Senate Armed Services Committee leaders want to know who to hold accountable.

Once touted as the largest change in Air Force logistics history, the Expeditionary Combat Support System was supposed to use Oracle enterprise resource planning software to finally establish the service’s first capability to globally view, standardize and manage $122 billion worth of MRO resources. It was supposed to help the Air Force save billions of dollars in the future while improving readiness. Computer Sciences Corp. has been the lead contractor.

Now it may just become the latest major program failure to serve as a reminder to other programs to get their acts in order.

“From what we know to date, this case appears to be one of the most egregious examples of mismanagement in recent memory,” Sens. Carl Levin (D-Mich.), committee chairman, and John McCain (Ariz.), the panel’s leading Republican, said in a letter to the Pentagon Dec. 5.

According to the letter, released publicly, the Air Force has received usable hardware and software with a value of less than $150 million from the program.

“We believe that the public and the taxpayers deserve a clear explanation of how the Air Force came to spend more than $1 billion without receiving any significant military capability, who will be held accountable, and what steps the [Defense] Department is taking to ensure that this will not happen again,” they added.

ECSS was initiated in 2004, but after being rebaselined the full-deployment decision and the full deployment for the first release only were scheduled for the first and fourth quarters of this fiscal year, 2013. The program itself had a life cycle estimate of $5.2 billion.

According to congressional auditors’ interviews with subject matter experts and analysis of the limited data, several areas of concern were identified, including data quality, data conversion, interoperability, usability, information assurance and requirements testability. For instance, ECSS was to have about 230 one-way interfaces, with roughly 120 to be implemented in Release 1. But the program’s Pilot A had only implemented two, so there were insufficient data to assess interface development, according to the February report from the Government Accountability Office.

In their letter, Levin and McCain request answers to several questions, including why earlier efforts to restructure the program were ineffective, as well as lessons learned and how to mitigate the loss of ECSS as the Pentagon races to make its financial accounting auditable.

The senators also want to know how industry will be held accountable. “What steps will the department take to ensure that the prime contractor’s failure to perform as required is appropriately considered as past performance in connection with future DOD contract award decisions?”