During the 1980s, many aircraft with aft-mounted engines, such as DC-9s, Boeing 727s, and MD-80s used powerbacks to reduce the number of ground personnel required.[1] For example, Northwest Airlines' fleet of DC-9 aircraft used powerback operations at certain airports, but discontinued the practice in 2005 citing the need to conserve fuel. KLM also avoids using the procedure for the same reasons, noting that powerbacks cause extra wear on the engines.[4]