Editing Fail-safe (section)

===Procedural safety===
As well as physical devices and systems fail-safe procedures can be created so that if a procedure is not carried out or carried out incorrectly no dangerous action results. 
For example:
*Spacecraft trajectory - During early [[Apollo program]] missions to the Moon, the spacecraft was put on a [[free return trajectory]]&nbsp;— if the engines had failed at [[lunar orbit]] insertion, the craft would have safely coasted back to Earth.
*[[File:FA-18-Afterburners.jpg|thumb|right|An aircraft lights its [[afterburner]]s to maintain full power during an [[arrested landing]] aboard an [[aircraft carrier]]. If the arrested landing fails, the aircraft can safely take off again.]]The pilot of an aircraft landing on an [[aircraft carrier]] increases the throttle to full power at touchdown. If the [[arresting wire]]s fail to capture the aircraft, it is able to take off again; this is an example of ''fail-safe practice''.<ref>{{cite web|first=Tom|last=Harris|title=How Aircraft Carriers Work|url=http://science.howstuffworks.com/aircraft-carrier4.htm|work=HowStuffWorks, Inc|date=29 August 2002 |access-date=2007-10-20}}</ref>
*In [[railway signalling]] signals which are not in active use for a train are required to be kept in the 'danger' position. The default position of every controlled absolute signal is therefore "danger", and therefore a positive action&nbsp;— setting signals to "clear"&nbsp;— is required before a train may pass. This practice also ensures that, in case of a fault in the signalling system, an incapacitated signalman, or the unexpected entry of a train, that a train will never be shown an erroneous "clear" signal.
*Railroad engineers are instructed that a railway signal showing a confusing, contradictory or unfamiliar aspect (for example a [[railway signalling#Colour light signals|colour light signal]] that has suffered an electrical failure and is showing no light at all) must be treated as showing "danger". In this way, the driver contributes to the fail-safety of the system.