Fortunately, the Titan's errant flight came to an end after flipping almost completely upside-down which caused the second stage to separate from the stack. The ISDS (Inadvertent Separation Destruct System) then activated and blew up the first stage. Most of the debris from the missile fell offshore or on the beach, and the second stage impacted the water mostly intact, although the oxidizer tank had been ruptured by flying debris from first stage destruction. Navy crews launched a salvage effort to recover the reentry vehicle and the guidance system from the sea floor. The reentry vehicle was found and dredged up along with parts of the second stage, but the guidance system was not recovered. The mishap was traced to an unforeseen design flaw in the silo's construction – there was not enough room for the umbilicals to detach properly which resulted in wiring being ripped out of the Titan. It was solved by adding extra lanyards to the umbilicals so they would have sufficient "play" in them to separate without damaging the missile. The flight was nonetheless considered a "partial" success in that the Titan had cleared the silo successfully. The inadvertent rolling motion of the vehicle may have also prevented a worse disaster as it added stability and prevented it from colliding with the silo walls as it ascended. While N-18 flew successfully from the Cape on 21 March, N-21 suffered another second stage failure after having been delayed several weeks due to another episode of the first stage thrust chambers breaking off prior to launch. This was followed by a launch from VAFB on 27 April when Missile N-8 flew successfully. N-14 (9 May), flown from LC-16 at the Cape, suffered another early second stage shutdown due to a leaking oxidizer line. Missiles N-19 on 13 May (VAFB) and N-17 on 24 May (CCAS) were successful, but of 18 Titan II launches so far, only 10 had met all of their objectives. On 29 May, Missile N-20 was launched from LC-16 with a new round of pogo-suppressing devices on board. Unfortunately, a fire broke out in the thrust section soon after liftoff, leading to loss of control during ascent. The missile pitched down and the second stage separated from the stack at T+52 seconds, triggering the ISDS, which blew the first stage to pieces. The second stage was manually destroyed by the Range Safety officer shortly thereafter.