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AVIONICS TECHNOLOGY (backlight) or reflector to produce images in color or monochrome. Unlike the CRT there is no need for high voltages driving internal components resulting in lower risk of electrical shock to repair personnel. The earliest discovery leading to the development of LCD technology was the recognition of liquid crystals in the late 1800s. In addition to low power con- sumption, LCDs are usually light weight and compact as compared to their predecessors. Depending on the method used for backlight- ing they provide little or no image flicker or geometric distortion. "Screen burn in" is also eliminated with this type of technology. Viewing angle can cause varia- tions in color and brightness and when left on for significant time periods without ample air circula- tion, partial screen overheat has been known to occur resulting in a discolored appearance of at least part of the displayed image. This is a temporary occurrence and will usually be self-resolving once cool down occurs. Heat is only part of the dilem- ma. Cold will also impact proper operation. Many LCDs utilize an internal heating element which is activated any time power to the display occurs and ambient temperatures are below a certain threshold. In this situation, opera- tion of the display may be inhib- ited until the internal components come up to a preset value which may take five minutes or more. This delayed startup has been misinterpreted as a failure and displays have been replaced sim- ply because ample time was not allowed for warmup to occur. Replacement In some cases replacement of lamps used for backlighting is an approved line maintenance function. Care should always be employed as damage can occur in the replacement process. Component or maintenance man- uals should always be consulted for guidance prior to performing any actions. Even though the use of elec- tronic displays often provide pilots relief in the event of malfunction, the aircraft minimum equipment list (MEL) should always be con- sulted to determine which indica- tions or indicators are considered critical for flight. AMT Jim Sparks has been in aviation for 30 years and is a licensed A&P.; He is the manager of aviation maintenance for a private company with a fleet including light single engine aircraft, helicopters, and several types of busi- ness jets. He can be reached at sparks- jim@sbcglobal.net. Oxygen & Nitrogen Booster Pumps yg Advanced Technology o ADDED SAFETY Automatic shut off when desired pressure is reac RUGGED&PORTABLERUGGED; & POR ABLE d Taugh mini- aughannock A ii mules, pail-pumps, completemules, pail-l cart systems & much more. hannock Av ation o er t systems & much more. lt Aiiiation offffers: il pumps, complete or bottled nitrogen. EASY-TO-USETO USE desired pressure is reached. R Lightweight and compact. Driven by compressed air or bottled nitrogen. perform other preÅ ight duties. Eliminate time consuming supply bottle top off, Free's up mechanics to consolidation, and cascading. 607-257-7500 Web: www.Å ytac.com or e-mail: garth@Å ytac.com or Fax 607-257-6419 TAUGHANNOCK GROUND SUPPORT EQUIPMENT 66 Brown Road Ithaca, NY 14850 Visit us at NBAA Booth #N2126 26 September 2011 Aircraft Maintenance Technology • www.AMTonline.com • www.AMTSociety.org