PRODUCT

The Mature Market for ELECTRIC ATTITUDE INDICATORS

B y J o s e p h E . ( J e b ) B u r n s i d e

he instrument panels in today’s the systems powering them have an tude indicators in the typical piston personal aircraft are truly mar- unenviable record of failures. Even airplane included only products that T velous. Compared with even 10 more troubling is the inability of many were heavy, expensive and rare — or a years ago, avionics in the typical pis- pilots flying in instrument conditions combination of all three. But demand ton single or twin leverages the revo- to recognize these failures and suc- from pilots who would rather fly their lutions in microprocessors and soft- cessfully control their airplane until a familiar aircraft than upgrade to one ware to present more information with safe landing can be made. with the latest and greatest “glass” greater accuracy than ever before. In their defense, one of the rea- panels has resulted in today’s mature With the advent of avionics systems sons some pilots prove incapable of market for electric attitude indicators. like the Garmin G1000, digital attitude handling such a failure is its insidi- Gone are the days when an owner and heading reference systems boast ous nature: Over a few minutes, the — and his avionics shop — might be reliability figures exceeding the typi- instrument would slowly start to lose forced to adapt something from a jet to cal airframe’s expected useful life. accuracy, adding to a pilot’s workload work in a piston airplane. Of course, new airplanes aren’t the and presenting bewildering informa- Today’s offerings are lighter and only ones flying: Thousands of older tion. Only recently were vacuum- and more reliable than their predecessors aircraft continue to give their opera- air-driven gyro instruments available and come with features making them tors excellent service — thank you with failure warning flags. easier to install and use in a wider vari- — using radios and other equipment In addition to more and better train- ety of aircraft than ever before. This with roots going back to World War II. ing, pilots and owners concerned about includes internal lighting, integrated That these aircraft continue to provide failure of their vacuum- and air-driven inclinometers for slip/skid indications, safe, efficient transportation is a testa- flight instruments can install an elec- selectable panel tilt for helicopters and ment to their engineers and the profes- tric backup. Typically, they choose an even battery backup. sionals maintaining them. But, even attitude indicator because it’s more Here are some highlights of what’s the most well-maintained airplane can safety-critical than the directional gyro available: have an Achilles’ heel: vacuum or air- — and the magnetic compass, for all driven flight instruments. its errors, already is coming along for Kelly Manufacturing Co. / Any aircraft flown in weather con- the ride. R.C. Allen ditions preventing flight by visual Recognizing the value of an electric The R.C. Allen line of gyro reference to the horizon is required backup attitude indicator, the FAA, instruments, produced by the Kelly to have a functioning set of flight in 2003, published Advisory Circular Manufacturing Co., includes the instruments powered by independent 91-75, “Attitude Indicator,” which RCA26 electric attitude indicators in sources. Usually, this means altimetry provides guidance to non-commercial the traditional 3-1/8 inch form factor. and airspeed instruments, using the operators of Part 23-certificated air- The instruments are available with or aircraft’s pitot-static system, electric planes (or airplanes certificated under without movable roll pointers, internal turn coordinator, attitude indicator earlier equivalent regulations) weigh- lighting and inclinometers. and directional gyro powered by an ing less than 12,500 pounds on substi- On request, the company also can engine-driven vacuum or air pump. tuting an approved attitude indicator incorporate custom color schemes to While any device can fail, vacu- for the rate-of-turn indicator. replace the traditional blue-over-brown um- and air-driven instruments and At first, the market for electric atti- presentation. All models in the RCA26

40 avionics news • november 2006 Installing the Electric AI

As avionics installations go, the electric attitude indicator is almost foolproof. Of course, it should be on its own circuit breaker, tied to the avionics buss and wired according to the FAA and the manufacturer’s recommendations. But that part of the installation is easy — the hard part can come when choosing a panel location for the new device. While the primary market for an electric attitude indicator is the piston-powered single or twin depending on air- or vacuum-driven primary gyros, panel space can be at a premium. This is especially true with older aircraft sporting original panels built before the standard “T” arrangement of flight instruments became common.

Kelly Manufacturing produces the RCA26. In many instances, it may be tempting to mount the new addition out of the pilot’s regular scan, perhaps on the panel’s far side. Don’t, even if the pilot/owner paying for line include a “pull-to-cage” handle. it agrees. The units are available in either 14v or Instead, installers should plan to place the electric attitude indicator close to the 28v configurations. existing flight instruments. This may mean some additional work to relocate some For more information, contact Kelly non-essential devices, but the effort is well worth it and should be supported by the Manufacturing Co. at 800-722-4976 customer. Why? Two words: Spatial disorientation. or visit www.kellymfg.com. On Oct. 16, 2000, a Cessna 335 piston twin crashed near Hillsboro, Mo., killing all three aboard. Night instrument conditions prevailed for the flight. Shortly after take-off Mid-Continent Instruments / from the St. Louis Downtown Airport in Cahokia, Ill., the pilot reported to air traffic The Lifesaver control the primary attitude indicator was not “reading properly” and that he had “his Mid-Continent Instruments is hands full.” Subsequently, the pilot said he was trying to use the attitude indicator on known throughout the general aviation the co-pilot’s side of the panel. industry for its repair, overhaul and Despite being properly trained and certificated for the flight — and despite there exchange services. Perhaps not so well being another certificated pilot aboard flying as a passenger in the cabin-class piston known is its development and produc- twin — the flying pilot lost control of the aircraft at 7,700 feet while attempting to tion of new products, including the execute a climbing left turn. 4200 (2 inch) and 4300 (3-1/8 inch) The National Transportation Safety Board determined the pilot’s failure to control line of electric attitude indicators, all the airplane and the subsequent loss of control resulted from spatial disorientation. of which are lit internally and operate Although the airplane was equipped with a second attitude indicator, it was located on 10v to 32v DC. on the far right side of the panel, a location the NTSB said required the pilot to make Definitely the pricier of the two, “frequent, rapid head movements to cross-check that instrument with the other instru- the 4200 series weighs only 1.5 lbs. ments.” and is designed for both fixed- and The NTSB concluded the “pilot’s head movements most likely caused him to experi- rotary-wing aircraft where panel space ence spatial disorientation.” is at a premium. The instrument can Although the backup attitude indicator in this accident was vacuum-powered, the same principle applies when choosing a location for one powered by electricity. Installers should work with their customers before installation begins and take great care to place backup instruments, like electric attitude indicators, in locations where pilots can cross-check them easily and without significant head movement.

be ordered with up to a 20-degree hand, is more affordable and flexible. panel tilt as well as in a configuration Needing the same voltage require- to match existing instruments or EFIS ments as its smaller sibling, options displays, minimizing a pilot’s need to available on the 4300s include a back- transition to them. up lead-acid battery providing up to

Mid-Continent Instruments’ 4300 series is Dubbed “The Lifesaver,” Mid- one hour of operation as well as front dubbed “The Lifesaver.” Continent’s 4300 series, on the other Continued on following page

avionics news • november 2006 41 ELECTRIC ATTITUDE INDICATORS The products listed here all are Continued from page 41 designed and marketed for certified panel annunciators. Like many of the aircraft; manufacturers, including electric attitude indicators available Falcon and Trutrak Flight Systems, today, the 4300 series is available with offer non-certified electric attitude a panel tilt specified by the customer. indicators for experimental aircraft. For more information, contact While redundancy in aviation often Mid-Continent Instruments at 800- is thought to require two engines and 624-6845 or visit www.mcico.com or two sets of aircraft systems, installing www.lifesavergyro.com. an electric attitude indicator can pro- vide an active instrument-rated pilot Sporty’s Pilot Shop / Castleberrry Instruments’ 2060 can be purchased through Sporty’s. with an extra margin of safety beyond Castleberry Instruments what might have been the industry Known for its charts and pilot sup- tion. It is available in either 14v or 28v standard when his or her airplane was plies, Sporty’s recently began offer- versions. manufactured. ing an electric attitude indicator The units are backlit and feature a Supplying an electric alternative to manufactured in the United States by pull-to-cage knob. Sporty’s offers a the “old-tech” air- and vacuum-driven Castleberry Instruments. Available in two-year warranty on its electric atti- gyro instruments in a customer’s air- the 3-1/8 inch form factor, the Sporty’s tude indicators. plane literally can be a lifesaver on product includes an inclinometer, For more information, contact that cold and rainy night when the enabling operators to move their turn Sporty’s Pilot Shop at 800-776-7897 primary gyro rolls over and dies. q coordinator to a more convenient loca- or visit www.sportys.com.

42 avionics news • november 2006