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The latest news from the Dutch Safety Board (Dutch)

Oorzaak crash NH90 bekend, verdergaand onderzoek nog nodig.

Oorzaak crash NH90 bekend, verdergaand onderzoek nog nodig.

Op 19 juli 2020 stortte een NH90-helikopter van de Koninklijke Marine tijdens een oefening bij Aruba in zee. Twee van de vier bemanningsleden kwamen daarbij om het leven. Direct na het ongeval startte de Onderzoeksraad voor Veiligheid, samen met de Inspectie Veiligheid Defensie (IVD), een onderzoek. In het verkennend onderzoek van de Onderzoeksraad wordt de directe oorzaak van de crash en de eerste bevindingen weergegeven. Het verdiepende onderzoek naar de mogelijk achterliggende factoren wordt door de IVD uitgevoerd.

Oorzaak crash NH90

De NH90 maakte deel uit van de het marineschip Zr.Ms. Groningen, gestationeerd in het Caribisch gebied. Het ongeval vond plaats tijdens het oefenen van deklandingen van de helikopter op het schip. Uit het onderzoek van de Onderzoeksraad blijkt dat de helikopter in de problemen kwam doordat het toestel, door het maken van een bocht, op gelijke snelheid kwam met de wind. Hierdoor hing het toestel als het ware stil in de lucht. Er is dan veel extra vermogen nodig om de helikopter in de lucht te houden. De vlieger zette extra vermogen in, maar door de lage vlieghoogte was het onmogelijk om de ingezette daling nog op tijd te corrigeren. De helikopter verloor snel hoogte en raakte binnen enkele seconden te water.

Vanaf het marineschip zag men de helikopter in zee storten en werd direct een reddingsoperatie ingezet. De twee inzittenden achterin het toestel konden zichzelf bevrijden en werden uit het water gehaald. De vlieger en de tactisch coördinator voorin de helikopter hebben zichzelf niet op tijd kunnen losmaken van het toestel en zijn verdronken. Uit het onderzoek blijkt dat de bemanning van Zr.Ms. Groningen grote inzet hebben getoond om hun collega’s te redden. Door de hoge golven en de beperkte capaciteit en toerusting aan boord was men echter niet in staat de redding met succes uit te voeren.

Onderzoek naar achterliggende factoren

Met het vandaag gepubliceerde rapport sluit de Raad het verkennend onderzoek af. Dit onderzoek geeft inzicht in de directe oorzaak van het ongeval, maar roept ook nieuwe vragen op over achterliggende factoren. Deze vragen hebben betrekking op de opleiding en training van de bemanning, de keuze om met één vlieger per NH90-helikopter te vliegen en de keuzes die zijn gemaakt over de toerusting van het marineschip Zr.Ms. Groningen. De Inspectie Veiligheid Defensie wordt aanbevolen deze vragen mee te nemen in het verdiepende onderzoek dat door de inspectie verder wordt uitgevoerd.

 

Bekijk hier de volledige onderzoekspagina 'Ongeval NH90-helikopter, Aruba'.

Dutch Safety Board shares view on emergency number malfunction investigations

The Dutch Safety Board has analysed three investigations that were carried out by three Dutch inspection services. They investigated an incident where the Dutch emergency number was unreachable for nearly three hours, due to a malfunction at the telecom provider. In a letter addressed to the minister of Justice and Security, the Board shares its vision on these investigations.

Investigation by three inspection services

The Dutch Safety Board decided not to launch an investigation following the incident, pending the outcomes of the three investigations. On 25 June 2020 the three investigation reports were offered to the House of Representatives, after which the Safety Board also analysed the outcomes.

Points of concern

Despite the thorough investigation by the inspection services and the useful conclusions, the Safety Board feels that certain subjects are not addressed in the reports. For example, the fact that the emergency number is dependent on one telecom provider and the vulnerability this poses is not addressed. A critical analysis of the emergency number chain is missing in the reports, even though the incident from 2019 - among with two earlier incidents in 2015 and 2017 - shows that a malfunction in one part of the chain affects the total. The Dutch Safety Board therefore questions the learning capacity of the parties concerned. 

By sharing these points of concern, the Board hopes to contribute to the effectivity of the measures to be taken by the minister.

Dutch Safety Board recommends annual technical inspections for large public buildings

There is insufficient insight into the structural soundness and safety of buildings once they are in use. Building owners do not see their duty of care as a pressing concern, and the government does not conduct active oversight. These are the conclusions reached by the Dutch Safety Board in relation to the collapse in 2019 of the roof of the AZ football stadium in Alkmaar. The Dutch Safety Board now recommends mandatory annual technical inspections for large public buildings. Jeroen Dijsselbloem, Chair of the Dutch Safety Board, commented: “In view of the conspicuously large number of collapses, the Safety Board believes that a mandatory periodic inspection of large buildings is necessary.”

Weakened welding joint

On Saturday, 10 August 2019, part of the grandstand roof of the AZ football stadium in the city of Alkmaar collapsed. At the time, the stadium had been in use for thirteen years. The Dutch Safety Board’s research shows that the steel roof construction did not meet the structural requirements when the stadium was completed. Within a few years, a crack appeared in one of the welding joints. During the time in which the stadium was in use, no thorough technical evaluations of the condition of the roof joints were conducted. As a result, it went unnoticed that one of the welding joints was growing increasingly weak. The roof eventually collapsed under a load which was far lower than the load which the structure was designed to withstand. During its investigation, the Dutch Safety Board therefore issued an interim warning for the welding joints in the remaining sections of the stadium’s roof in August of 2019.

Sixty incidents in 20 years

The investigation shows that the collapse at the AZ stadium is not an isolated incident. An inventory carried out by the Board has found that serious structural defects in more than 60 buildings have come to light over the past 20 years. This is not the Board’s first investigation as a result of an incident related to the construction industry: in 2017 it investigated the collapsed car park at Eindhoven Airport, in 2011 it looked into the collapsed roof of the Grolsch Veste stadium in Enschede and in 2010 it conducted an inquiry following the collapse of the concrete floor of B’Tower in Rotterdam. Following the investigation into the collapse of the car park in Eindhoven, the construction industry drew up an action plan to improve structural safety checks during the design and construction phases of buildings. However, once a building has been taken into use, such checks tend to fall by the wayside.

Responsibility

Building owners are responsible for the structural safety of their properties, but the law does not prescribe how this should be monitored. When a building is in active use, structural safety incidents can have major consequences for the people inside. Jeroen Dijsselbloem: “The users of a public building must be assured of the building’s safety and soundness. This requires building owners to be alert to the structural safety of their buildings.” That is why the Board recommends that the Minister of the Interior impose a legal obligation on owners of publicly accessible buildings to commission periodic structural safety inspections.

 

 

The full investigation page with the report, the recommendations, and the short video can be found here.