efferson City, Mo. ? The airline whose plane crashed in Jefferson City last week has decided to lower the maximum altitude at which its planes can fly, as federal investigators said the engines failed when the plane was at its highest point.

The National Transportation Safety Board provided that information and other details in an update on the investigation Wednesday afternoon.

The plane crashed Thursday night in a residential neighborhood about two miles from the city’s airport, killing the pilot and co-pilot. No passengers were aboard.

Federal investigators have said they were studying whether altitude contributed to the loss of engine power.

Data indicates the 50-seat Pinnacle Airlines CRJ2 was flying at its maximum altitude of 41,000 feet at 9:52 p.m., when it was about 100 miles south of Jefferson City. The NTSB said Wednesday that the flight data recorder showed both engines failed at about the same time at 41,000 feet.

The board also said Pinnacle had decided to restrict its planes’ maximum altitude to 37,000 feet.

The jet had taken off from Little Rock, Ark., and was en route to Minneapolis. Pinnacle Airlines flies regional routes as part of Northwest Airlines’ Northwest Airlink.

NTSB officials said earlier that the jet had aborted a scheduled flight with passengers from Little Rock Thursday morning after an indicator light went on for part of its bleed-air system. The system pulls hot, compressed air from the engines to heat other components. An airplane indicator light signaled a potential problem with the bleed-air sensing loop, which uses heat to determine if air is leaking from the engine.

The plane’s loop was replaced before it took off for Minneapolis on Thursday night, and the NTSB said it found that maintenance work was done properly.

The plane’s engines were being sent to Massachusetts for further investigation, while other parts of the wreckage were headed to Rantoul, Kan., the board said.