Turnout protection for aircraft tractor

In combination with:

• an aircraft extending along a longitudinal aircraft axis and having a nose wheel pivotal about an upright wheel axis;
• and
• a tractor extending along a longitudinal tractor axis and adapted to engage the nose wheel and tow the aircraft, whereby the tractor and aircraft axes can extend at an angle to each other that should not exceed a predetermined maximum turnout angle,
• a turnout protection system comprising:
• radiation-reflecting structure on the aircraft that extends generally parallel to the aircraft axis and is reflectively effective transversely of the aircraft axis and that is only oriented generally perpendicular to locations on the tractor when the aircraft and tractor axes extend generally at the maximum turnout angle relative to each other;
• means including a pair of electronic sensors on the tractor at the locations directed toward the aircraft and each including
• transmitter means for outwardly emitting a fan-shaped beam of radiation reflectable by the structure having a horizontal beam spread angle of at most 20.degree. and a vertical beam spread angle of at least 45.degree., and
• receiver means immediately adjacent the transmitter and directed outwardly along the beam, whereby the beam will be reflected back into the receiver means substantially only when the structure is generally perpendicular to the beam;
• and
• control means on the tractor for taking action when either of the electronic sensors detects that the aircraft and tractor axes extend generally at the maximum turnout angle relative to each other.