The Bundeswehr took delivery of the first N90 Sea Lion chopper a month ago, but “because of the inadequate and incomplete documentation, it is not possible” for the Navy's personnel to fly the helicopters.
Irregularities were found in “well over 150 positions” in the technical documentation that describes how to use, maintain and repair the chopper.
“In all, these are considerable errors that do not permit the safe operation of the flight for the moment,” added the army on Wednesday.
The Bundeswehr has ordered a total of 18 Sea Lion helicopters with deliveries set to be completed by 2022.
The latest equipment woe is just one in a long-list of embarrassing problems plaguing the German army.
Just two weeks ago, the air force said it refused delivery of two Airbus A400M transport planes due to technical faults.
In recent years, the army has also been forced to phase out the G36 assault rifle after reports it failed to shoot straight at high temperatures.