Lieuwe de Vries for Veenstra & de Vries Aviation Publishing
Serious corrosion problems and manufacturing defects have caused The Netherland’s defence ministry to halt further deliveries of the NH-90 helicopter intended for use by the Royal Netherlands Navy. The resulting gap is to be filled by increased operations by Cougar helicopters.
The helicopter that has already been plagued by delays in production and testing has recently seen use aboard Royal Netherlands Navy Frigates during anti-piracy operation ATALANTA of the coast of Somalia. The helicopter returned showed much higher levels of corrosion then was to be expected. Further investigation by the Dutch National Aviation Research institute showed extensive design and construction errors leading to these flaws.
One of the RNLAF’s NH-90’s coded N227, this airframe is a Meaningful Operation Capability helicopter. Aircraft shown here flying a display at Gilze-Rijen Open House earlier this month, while announcers at that time still claimed that all problems have been ironed out they appear to have been wrong.
The problems with the NH-90 range from absence of sealant in locations where it should have been applied according to design specifications to a tail folding mechanism that seems ill-designed for a helicopter based on a frigate. When the tail was folded area’s were exposed in the aircraft where water could pool and did not drain by it self. In other places materials were chose that were not up to operations in a corrosive environment. Additionally, despite extensive rinsing and cleaning of the aircraft after operations in saline environments, extensive salt build up was still found in areas due to poor design.
The two aircraft inspected were basically of two versions, one being a “Meaningful Operational Capability” (MOC) version and the other being a “Full Operational Capability” (FOC). The MOC version can be viewed as a sort of early production prototype which has most of the features of the ultimate production machines but has been made using different materials in some places. In the Dutch NH-90’s case the FOC machine had been adapted following early corrosion inspections of the MOC helicopter. These adaptations don’t appear to have worked though, the adapted machine showed as high levels of corrosion despite lessons learned from the earlier machine and despite having been based on a ship with a much higher helicopter deck which does a better job of protecting it from salt water spray.
Development and purchasing of the NH-90 is handled through NATO’s NAHEMA office, a joint funding project in which countries participate to develop and purchase NH-90 helicopters. The machines are produced by NHIndustries and purchased by NAHEMA under French law. The Dutch Defence Minister wrote in a letter to parliament that she feels that the manufacturer is taking the problems seriously and has found solutions for 60 percent of the problems. However, who will pay the bill for rectifying these problems as well as the costs of additional Cougar operations is uncertain at this moment hence the decision to stop further deliveries.
The gap left in the already increasingly meager Dutch rotary wing capacity will have to be filled by the Eurocopter Cougar. Though the Defence Helicopter Command originally planned to keep eight Cougar’s operational further examples will now be brought back into service. One example will be based in the Dutch provinces in the caribbean, the US Coast Guard will also base one of it’s helicopters on a Royal Netherlands Navy Vessel during certain periods. Search and Rescue tasks during the hours of darkness will be transferred to a commercial entity.