The Norwegian Navy has tested landing NH90 helicopters on the deck of its ships using a testing method devised by Dutch aerospace research company NLR. The testing strategy is said to have halved the flying time needed to complete the testing.
The objective was to determine the operational limits within which the NH90 helicopter is able to safely land on two of the Norwegian navy’s ships in open sea.
The SHOL (ship helicopter operational limitations) testing was performed using a procedure NLR developed in the 1980s to reduce the number of required test hours at sea.
In this instance, a total of 308 landings were carried out over approximately 40 hours of flying time, spread over the course of one week. This timing meant that on average, there was a landing every four minutes.
NLR’s method includes testing ship models in one of DNW’s wind tunnels in order to understand the airflow around the ship. The second phase consists of shore-based trials that expose helicopters to different windspeeds on land.
The resulting candidate flight envelope – the combination of the data obtained from wind tunnel tests and on-shore tests – then has to be tested and validated in real life at sea.