The Metropolitan Washington Airports Authority is examining the accuracy of repair records for its fleet of shuttle buses at Dulles International Airport, officials said Wednesday, following questions about the accuracy of the odometer readings in some of the records.

The Washington Post reviewed 300 pages of maintenance reports for some buses after operators complained that the vehicles, which are used to carry passengers and employees between parking lots and the main terminal, are old and unsafe.

The drivers said the buses have had bad brakes and transmissions, worn-out tires, inoperable turn signals, poor suspensions, oil leaks and broken air-conditioning units. The Post reviewed records for four buses that drivers said were the worst performers.

Several drivers spoke on the condition of anonymity because they said they feared retribution.

The records, from September 2010 to August 2011, showed that three of the buses were broken down every month, with a range from one to 13 days. The fourth bus had one month when no problems or repairs were reported. Most problems were repaired within 24 to 72 hours.

The records of two of the buses listed inconsistent odometer readings.

On May 10, Bus 313 had 264,276 miles according to a maintenance report, but that figure dropped to 235,722 on a report for May 23.

Readings for another bus — No. 306 — varied more.

On March 13, the odometer on Bus 306 said it had 193,984 miles, according to a repair order. Later records showed wide fluctuations. The odometer read 378,550 miles on April 21, but on April 25, it read 196,169. On July 7, it read 378,580 miles, but dropped to 205,656 on Aug. 24.

Chris Browne, vice president and airport manager at Dulles, said Wednesday that the authority, which operates Dulles and Reagan National Airport, “didn’t look at the records closely” before releasing them. However, he said he believes the readings are the result of a “clerical error.” The records are entered by a mechanic in a repair shop and then entered into a computer by another person, he said.

Tara Hamilton, a spokeswoman for MWAA, said that the airport authority’s contract management staff reviews on a monthly basis “the fleet maintenance database” for its buses, looking for “trends and anomalies.” Those reviews do not include the individual repair order tickets given to The Washington Post, she said.

The inconsistent odometer readings on Bus 306, Browne said, would be examined more closely. He said other maintenance records for the other 42 buses in the fleet would also be checked.

“We are investigating right now,” he said, noting that he’s asked the lead contractor on the shuttle bus service — Standard Parking of Chicago — to look into the matter.

Browne said he’s asked the contractor to determine “what accounts for the discrepancies in the odometer readings, what’s the extent of the problem, why is it happening and how to fix it.”