Airline aircraft maintenance and ground support services meet at the connection points for ground service. Ground power must be applied to the aircraft, but responsibility for the aircraft receptacle falls to aircraft maintenance. This responsibility gap is not currently being addressed by the industry. For years any difficulty in applying power to an aircraft on the ground has been blamed solely on the ground power cable or generator. Any potential problems with the receptacles was largely ignored by ground service personnel, since they are not allowed to touch the aircraft.
No one thought to look closely at the receptacle as a potential source of the inability to reliably apply power to the aircraft (in fact, routine maintenance A,B,C or D maintenance did not routinely check or change the receptacle). Recently WPI Burton Electrical Engineering began an investigation into the most common problems associated with the inability to power the aircraft and found a significant number of badly worn pins in the receptacles.
By means of a “No-Go” contact gage we found that nearly 95% of the aircraft on the ground at one major airport belonging to one airline had undersized contacts due to insertion wear.
Undersized contacts in an aircraft receptacle will cause arcing when a line opens under load. This arcing will burn the cable or the contacts severely. This arc flame will reach temperatures of over 23,000 degrees at the receptacle contact and could result in a temperature rise at the receptacle contacts of over 2,390 degrees Fahrenheit in one minute.
This paper introduces a “replaceable contact” receptacle that will allow a the airline to change out undersized contacts in a matter of minutes. This change-out of undersized contacts will avoid the arcing and resultant temperature rise as well as the lack of proper plug to receptacle contact when ground maintenance personnel attach a cable to the aircraft.