A shutoff valve , preferably a crash valve, for interrupting a gas flow, comprising: a gas inlet ; a gas outlet ; a closure device disposed in the flow direction between the gas inlet and the gas outlet; an inertia body mounted in a pendulum fashion; wherein the closure device is movable from an open position into a closed position along a direction of movement; wherein the closure device is biased in the closed state; wherein the closure device comprises a supporting member, preferably a structure protruding in the direction of movement, which is moved together with the closure device so that the supporting member takes a first position in the open state and a second position in the closed state; wherein the inertia body is configured to take an idle position in which the inertia body is aligned in parallel to a first axis defined by the direction of movement of the closure device and a deflected position in which the inertia body is inclined with respect to the first axis; wherein the inertia body is configured to return on its own from the deflected position to the idle position; wherein in the idle position the inertia body holds the supporting member in the first position so that the closure device is prevented from returning to the closed position; wherein the inertia body is configured such that it is moved from the idle position into the deflected position by an occurring acceleration force when a predetermined acceleration is exceeded so that the supporting member assumes the second position and the closure device assumes the closed state; wherein the inertia body is disposed between the gas inlet and the gas outlet in the flow path; and characterized in that , when the inertia body is in the deflected position and the supporting member is in the second position, the supporting member prevents the inertia body from returning to the idle position. a gas inlet ; a gas outlet ; a closure device disposed in the flow direction between the gas inlet and the gas outlet; an inertia body mounted in a pendulum fashion; wherein the closure device is movable from an open position into a closed position along a direction of movement; wherein the closure device is biased in the closed state; wherein the closure device comprises a supporting member, preferably a structure protruding in the direction of movement, which is moved together with the closure device so that the supporting member takes a first position in the open state and a second position in the closed state; wherein the inertia body is configured to take an idle position in which the inertia body is aligned in parallel to a first axis defined by the direction of movement of the closure device and a deflected position in which the inertia body is inclined with respect to the first axis; wherein the inertia body is configured to return on its own from the deflected position to the idle position; wherein in the idle position the inertia body holds the supporting member in the first position so that the closure device is prevented from returning to the closed position; wherein the inertia body is configured such that it is moved from the idle position into the deflected position by an occurring acceleration force when a predetermined acceleration is exceeded so that the supporting member assumes the second position and the closure device assumes the closed state; wherein the inertia body is disposed between the gas inlet and the gas outlet in the flow path; and characterized in that , when the inertia body is in the deflected position and the supporting member is in the second position, the supporting member prevents the inertia body from returning to the idle position. <EOS>