The US Air Force says it "elected not to launch" the second prototype Boeing-built X-51A hypersonic vehicle from the B-52H mothership the morning of 24 March.
According to officials, the air force flight test centre B-52 departed Edwards Air Force Base carrying the X-51A under its left wing shortly before 9:00am local time and "flew as planned to the designated launch area" over the Navy's Point Mugu sea range.
Test controllers however "opted not to initiate the test since all required test conditions could not be met", the air force says. No additional information has been provided by the air force, Boeing or scramjet engine provider, Pratt & Whitney Rocketdyne.
©US Air Force
"The next flight test attempt will be rescheduled following a check of the system and when range and test assets can again be aligned," the air force says.
Officials hope to achieve a 300s burn of the JP-7 fuelled engine up to 6.0M on the second of four flight test vehicles in the program.
During the first test in May 2010, controllers destructed the vehicle after 143s of hypersonic flight due to loss of telemetry, a problem investigators later tied to a leak in a thermal seal at the interface between the engine and the airframe, which allowed hot gases to enter the flight vehicle.
P&W and Boeing later redesigned the seal and modified the remaining vehicles.