A sharply critical legislative audit of the state's medevac operation could jeopardize the General Assembly's willingness to spend more than $100 million on overhauling the state police unit's aging 12-helicopter fleet, a key lawmaker said yesterday.

According to the audit report, about a third of the state's emergency medical response helicopter fleet was out of service for 51 individual days during the past fiscal year, and the state police Aviation Command didn't adequately track critical data such as maintenance needs and the cost per flight hour.Moreover, because of data reliability problems, auditors could not verify state police claims that about 95 percent of flights bring patients to the hospital within the so-called "golden hour," a crucial time frame for emergency medical care.

"You'd sure like to think they're taking care of taxpayers' money a little better than it appears," said Sen. John C. Astle, an Anne Arundel County Democrat and retired helicopter pilot who sits on the committee that commissioned the audit. "I think there are going to be some pretty serious questions. ... I could see where the General Assembly might say, 'Wait a second, we're not willing to give you that kind of money until we have strong assurances it's going to be used in a particular way.' "

A September hearing about the audit is scheduled before the Joint Audit Committee, which requested the review last year amid concerns about aging aircraft and employee complaints of high turnover, low salaries and limited advancement opportunities at the Aviation Command, said Del. Steven J. DeBoy, co-chairman of the committee.

DeBoy, a Baltimore County Democrat and retired police officer, said he expected "tough questions" at the hearing but praised the medevac unit's cooperation with the audit and emphasized his strong belief that the helicopters ought to be replaced as soon as possible. "I don't doubt for one second they need to be replaced," DeBoy said. "This is a public safety issue."

Bruce A. Myers, the state's chief auditor, said the 98-page report should raise questions about the reliability of the Aviation Command's claims that its entire helicopter fleet ought to be replaced with new aircraft - an overhaul budgeted by the General Assembly at about $120 million over the next four years.

"I think there's a strong indication that you probably need some new [helicopters] but I don't know if you can tell the extent of that need," Myers said. "Is 12 the right number? I don't know. How bad are the 12 you have now? They don't have those kinds of records."

The state transportation department is preparing to solicit bids for new helicopters this fall and plans to purchase three during the current fiscal year, with additional helicopter purchases planned at three a year through fiscal year 2012.

The audit was conducted over an eight-month period in 2007 and 2008, during which more than 110 of the Aviation Command's 140 employees were interviewed by state auditors.

Among the key findings:

* During fiscal year 2007, six of the 12 helicopters were individually unavailable for more than 120 days.

* The unit did not maintain up-to-date operations and maintenance manuals for helicopters, keep critical parts in stock or effectively manage parts inventories.

* A lack of reliable data kept by Aviation Command made it impossible for auditors to assess whether the medevac program transported patients to hospitals within a 60-minute window.

* High staff turnover in "key positions" is a "significant issue" for the state police unit.

Despite finding numerous managerial deficiencies at the state police's Aviation Command, the Office of Legislative Audits praised the medical emergency response unit for its "impeccable safety record" and dedicated employees. Auditors also found insignificant use of the aging 12-helicopter fleet for "non-critical missions" such as public relations tours, which DeBoy said had been an area of concern among lawmakers.

Myers said his auditors could not determine whether the unavailability of certain helicopters on any given day impeded the unit's mission capabilities.

On days when fewer than eight helicopters were available - meaning that one of the medevac unit's eight bases was not fully functional - "we were unable to see if they had to turn down calls or anything like that," Myers said. "We can't point to a case where they didn't perform, but we just think management should have a lot more information to allow them to make ... decisions in running the place."

Greg Shipley, a police spokesman, said the law enforcement agency was "very pleased" with the audit, particularly its recognition of the aviation unit's safety record, which exceeds national averages. Shipley said police officials have already taken steps to implement many of the auditors' recommendations, such as keeping better records, but would require additional funding to maintain the types of computer databases suggested.

As for the maintenance issues - such as helicopters sidelined for months while waiting for repairs or inspections - Shipley said those are largely a function of an aging fleet and competing military demands for similar aircraft maintenance in recent years.

The Department of State Police Aviation Command is the state's primary provider of emergency medical transport of patients to hospitals, and also conducts various other missions, such as search-and-rescue and damage assessment. It operates 12 American Eurocopter Dauphin helicopters - most purchased in 1989 and 1990 - and two airplanes out of eight bases around the state.

Over the past five years, the program has flown more than 40,000 missions, including 24,500 medevac missions. There have been no major accidents, injuries or fatalities associated with the helicopter fleet since 1989, a track record that is better than national statistics kept by the National Transportation Safety Board, the auditors noted.

Shipley said the survival rate of critically injured patients transported by air to Maryland Shock Trauma Center has consistently been above 90 percent.

In its written response to the audit, the Aviation Command accepted most of the auditors' recommendations, such as the need to implement better data-tracking and maintenance systems. It disputed auditors' findings of high staff turnover but agreed to study employee retention trends and, if necessary, take steps to increase salaries. Shipley noted that helicopter maintenance technicians and supervisors received a pay increase in July 2007.