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Just 5 minutes and thirty seconds after launch of Apollo 13 Jim Lovell and his crew would experience their first anomaly on the mission.

During the burn of the S-II stage the center engine cuts off at 330 seconds into the mission (132 seconds earlier than planned).

Jim Lovell makes the call “inboard” to signify that the Center engine has cut out. Engine number 5 on his control panel lights up to make the crew aware of the anomaly.

In the movie this is shown as a flashing light for dramatic effect. In reality all the lights were off and number 5 came on, in a steady state, to indicate there was a problem.

In the MOCR CAPCOM Joe Kerwin acknowledges the call just 4 seconds later. Flight controllers can already see on their trajectory plots that the flight is off nominal.

Post flight analysis shows the actual thrust of the second stage compared to what had been planned. Jack Swigert does some quick maths and announces “that’s 2 minutes early”.
The center engine was experiencing acceleration forces of 33G and tripped a switch to shut it down.

Shortly before this anomaly the crew confirm “we are EDS manual”. The crew would initiate the Emergency Detection System manually to start the abort sequence. They are monitoring the flight of the Saturn V and concerned about the early shutdown of the engine.

However there is little the crew can do other than ride it out. Mission Control do not call for an abort. In fact the second stage can lose another engine and the mission would still continue as the 3 remaining would burn all the fuel left.

The engines on the second stage burned for 34 seconds longer than planned.
The single J-2 on the third stage burned 9 seconds longer than planned.

Despite this anomaly Apollo 13 achieved an Earth Parking Orbit just 1.9 ft/sec slower and 0.2 miles higher than planned.

The German engineers at Marshall were conservative in their design of the Saturn boosters and wanted solid redundancy in the systems.

NASA demonstrated “engine out” capability with the first generation of the Saturn launch vehicles in 1963. On flight SA-4 an inboard engine was deliberately shut down whilst fuel was feed to the remaining engines to compensate.