parts of the rails and all relevant bogies were stored in an empty hangar at Celle Air Base until the investigation into the cause of the accident was completed. Equipment Celle Air Base is a controlled military airbase where visual and instrument flights are allowed. It is surrounded by a control zone of airspace class "D" which is active during the hours of operation. The area of responsibility is classified as "E". Since the air base is mainly used as a training site for helicopter pilots, several grassy areas parallel to the runway are used for the training of emergency landing procedures, for example autorotation and engine failure. In order to decrease the noise level for the inhabitants of Celle, the city having expanded towards the air base over the years, an additional helicopter training site at Scheuen (north of Celle) is used. Celle Air Base is equipped with a non-directional beacon (Frequency: 311 MHz, Identification: CEL). This is used for approach and departure procedures of Celle as well as for the airports Hanover and Braunschweig-Wolfsburg and as a waypoint for two airways (J803 und T803) in radio navigation. Additionally, the airfield is equipped with a precision approach radar (PAR-80) and airport surveillance radar (ASR-910). On the air base an Aeronautical Information Service, a section of the Met Office and a fire brigade are located. All services needed for national and international flights are kept available. Celle Air Base is an airport of entry and can be flown to directly from abroad. For parking and maintenance of aircraft five hangars are used. Each hangar may keep up to 24 helicopters. The apron offers space for about 40 aircraft of various types. Additional space is offered in the north-, the southwest- and southeast-spider. These are spider-like platforms for aircraft, partly covered with trees and bushes as during the Cold War. Most of these platforms are no longer in active use but can be activated for military exercises. Jet fuel is provided by tank lorries. A subterranean refuelling station with filling abilities close to the taxiway is available but used only very occasionally. Arresting gear is not available. Heeresfliegerinstandsetzungsstaffel 100 (Army Aviation Maintenance Squadron 100) is a specialised unit and unique within the German Army. It performs the highest grade of maintenance for the helicopter Bölkow Bo-105 and is therefore responsible for all helicopters of this type used in the German Army.