When Armstrong noticed they were heading toward a landing area that seemed unsafe, he took manual control of the LM and attempted to find a safer area. This took longer than expected, and longer than most simulations had taken. For this reason, Mission Control was concerned that the LM was running low on fuel. On landing, Aldrin and Armstrong believed they had 40seconds of fuel left, including the 20seconds' worth which had to be saved in the event of an abort. During training, Armstrong had, on several occasions, landed with fewer than 15seconds of fuel; he was also confident the LM could survive a fall of up to . Post-mission analysis showed that at touchdown there were 45 to 50seconds of propellant burn time left.