MBB the Bo 105 is cleared for up to 3.5 positive G force and one negative. One benefit of the Bo 105's handling and control style is superior takeoff performance, including significant resistance to catastrophic dynamic rollover; a combination of light weight and the twin-engined configuration enables a rapid ascent in a performance takeoff. Perhaps the most significant feature of the Bo 105 is its rotor blades and rotor head. The rotor system is entirely hingeless, the rotor head consisting of a solid titanium block to which the four blades are bolted; the flexibility of the rotor blades works to absorb movements typically requiring hinges in most helicopter rotor designs. The rotor blades are made from reinforced-plastic glass-fiber composite material; the flexibility of the main rotor allows for active elements other than rotor pitch changes to be removed, greatly simplifying maintenance and extending blade lifespan. The reliability of the advanced rotor system is such that, in over six million operating hours across the fleet, there was a total of zero failures (as of 1991). The rigid rotor blade design adopted on the Bo 105 has been partially responsible for the type's agility and responsiveness; it remained an uncommon feature on competing helicopters throughout the Bo 105's production life. Military operators would commonly operate the type at a very low altitude to minimise visibility to enemies, the Bo 105 being well matched to such operations, as the helicopter's flight qualities effectively removed or greatly minimised several of the hazards such a flight profile could pose to pilots. When outfitted with optional auxiliary fuel tanks, a basic model Bo 105 had a flight endurance of roughly five hours under load. In the event of a single engine failure, the Bo 105 could typically continue its flight, albeit with a reduction in cruise speed and range. Besides the two pilots, the cabin can be configured to accommodate up to three passengers on a single rear bench, which can be removed to make room for cargo or a stretcher, which can be loaded and unloaded via the large clamshell doors located at the rear of the fuselage. In a maritime context, the BO 105 can be equipped with auxiliary fuel tanks, emergency flotation equipment, an inflatable life raft, folding rotor blades and high skid landing gear. Operational history In 1975, the German Army decided to procure a specialist anti-tank version armed with up to