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Saturday, April 1, 2000

The Promising Future for FDRs and CVRs

Both new regulations and new functions give on-board recording systems a big boost in their important to air safety -- not to mention to unit sales and installations

James W. Ramsey

The "black box" industry – provider of safety/investigation-critical flight data recorders (FDRs) and cockpit voice recorders (CVRs) – is getting a healthy boost today from more stringent government requirements in the wake of recent aircraft accidents. What triggers this boost are several potential requirements:

  • Dual recorder units in the aircraft;

  • Independent backup power sources;

  • Longer duration CVRs;

  • Increased parameter FDRs; and

  • Combining FDR/CVRs into a single unit.

Such requirements would spur additional purchases of FDRs and CVRs for both new aircraft and retrofit on older planes.

The U.S. Federal Aviation Administration (FAA) was scheduled to propose new FDR/CVR rules by March 1. These are based on National Transportation Safety Board (NTSB) recommendations following the crash of a Swissair MD-11 off Nova Scotia in September 1998. Both recorders stopped working approximately six minutes before the MD-11 plunged into the North Atlantic.

The NTSB, therefore, recommended a 10-minute independent backup (battery or capacitor) power supply for both the FDR and VCR. This would keep these systems running despite electrical failure or shut down. In addition, the NTSB recommended that redundant units be installed in both the front and rear of the aircraft.

"We agree with the intent of both recommendations and will propose rules addressing both," an FAA spokesman told Avionics Magazine. FAA also endorses NTSB’s recommendation to extend CVR recording time beyond the 30 minutes currently required in the United States to 120 minutes. (In Europe, government agencies already mandate 120 of minutes recording time).

The U.S. agency also will propose that aircraft built after Jan. 1, 2003 have combination voice and data recording systems, one unit located close to the cockpit, the other in the back of the aircraft. This would further assure the retrieval of operating recorders following a crash.

The current proposed rules follow ones enacted in July 1997. Then, the FAA mandated that FDRs collect more flight information–increasing the minimum number of parameters from 11 to 17 on older aircraft and up to 88 for newly manufactured aircraft. The rule called for retrofit of several existing aircraft during maintenance checks over a four-year period.

Required in the U.S. on all aircraft carrying 10 or more passengers in scheduled revenue service and installed on many business aircraft, FDRs and CVRs record information that helps investigators reconstruct the events leading to an aircraft accident. The CVR records radio transmissions and sounds in the cockpit, while the FDR monitors operating data from aircraft systems relating to airframe, engines and avionics systems.

Protection for the systems, conventionally installed in the aircraft’s tail section, has advanced. The boxes now are housed in hardened stainless steel (or titanium) capsules to counter intense fire or heat and to cushion them from impact. Today’s units can withstand heat up to 2,000� F (1,100� C)–the temperature of a jet fuel fire–for 30 minutes and a crash impact of 3,400 Gs.

Recorders have evolved from the metallic foil systems of the late 1950s to those using magnetic tape (many of which remain in use today) to the modern solid-state recorders. The solid-state recorders, introduced in 1993, store flight information or cockpit sound on computer memory chips.

Some solid-state flight recorders keep track of more than 700 parameters, including vertical and longitudinal acceleration, position of flight control surfaces, engine thrust, pitch and roll attitude, and control column position. The FDRs record parameters for 25 hours, after which they "recycle" and overwrite old data with new.

The CVR is a four-track voice recorder that records audio from the pilot and co-pilot, passenger announcements, and cockpit sounds picked up by an area-microphone mounted on the cockpit ceiling. Typically, each track, or channel, is stored on a 30-minute recording loop after which the newer recorded material replaces the oldest.

Several companies dominate the FDR/CVR industry in the United States: Honeywell (formerly AlliedSignal), Teledyne Controls, L-3 Communications, Universal Avionics, and Smiths Industries. Europe includes SFIM and Penny&Giles. Other companies, such as ECS (Electronic Cable Specialists) and Dukane Corp. provide the support structure, wiring, and the acoustic underwater directional beacons used to locate the recorders. Companies such as Avionica produce quick access recorders.


AlliedSignal (now Honeywell) has produced flight recorders for more than 40 years, tracing its heritage to Sundstrand Data Control. The company has produced solid-state recorders since 1993, and currently provides its ED 55 solid-state flight data recorder (SSFDR) and ED-56A digital cockpit voice recorder (DCVR) for commercial airliners.

It also provides a smaller, lighter version of these systems, called the advanced recorder (AR) series for use in business and general aviation aircraft and helicopters. These units weigh 8.8 pounds (4 kg) and are designed to require no scheduled maintenance. The AR CVR records four audio channels for 30 or 120 minutes. The AR FDR records at data rates of 64,128 or 256 words per second for 25 hours.

Honeywell also produces a combi–combined flight data and cockpit voice recorder–currently aimed primarily at the business aircraft and helicopter market. But the manufacturer also sees a strong possibility of expanding this product to the commercial airline market to satisfy the possible FAA requirement to have a second FDR/CVR unit in the aircraft’s nose.

Teledyne Controls

Teledyne Controls is a major supplier of digital flight data acquisition units (DFDAUs), which sort and feed data to the FDRs and CVRs, according to Steve McDonnell, manager, data acquisition and recording for the Los Angeles, Calif.-based company. "We make the smart part of the system that makes all the decisions, and we work directly with the airlines, the OEMs [Boeing and Airbus], and with the mod [modification] houses."

Last year, Teledyne Controls demonstrated the transmission of information from an on-board DFDAU to a ground-based data analysis computer using the Internet. The company now produces a wireless ground link, which takes advantage of the Net and negates the need to install and manage a network of receiving towers.

L-3 Communications

Formed in 1997 from divisions of Loral and Lockheed Martin, L-3 Communications designs and produces aviation recorders at its Sarasota, Fla., facility. L-3 officials claim their company has delivered more than 40,000 units. L-3 markets the recorders under the name Fairchild Aviation, which began producing them in the early 1960s.

L-3 currently offers the FA2100, A200S and A100S solid-state CVRs; the FA2100 and F1000 solid-state FDRs, and an FA2100 combined CVR/FDR. The company boasts that its A200S provides redundant recording of the last 30 minutes of audio.

The flight data recorder recovered from the Swissair crash was a Fairchild F1000 and the CVR recovered from the Egyptair 767-300 accident in October 1999 off the coast of Nantuckett, Mass., was a Fairchild A100.

Universal Avionics

Universal Avionics, in Tucson, Ariz., produces what it calls "second generation" solid-state CVRs. The CVR-30B and CVR-120 record 30 and 120 minutes, respectively. Both recorders weigh 13.2 pounds (6 kg) and accept four channels of cockpit audio, which is converted to digital format and stored in solid-state non-volatile flash memory. In addition, Universal makes available a portable test set that controls CVR operations, and features diagnostic capabilities. Looking to the future, Universal has included provisions for data link input in the recorders.

Penny & Giles

Penny & Giles Aerospace Inc. offers a one-piece multipurpose FDR/CVR that weighs less than 9 pounds (4.1 kg) and meets all new requirements, according to Bill Major, director of sales and customer service. The units are built both in the UK (at Christchurch, Dorset) and the Wichita, Kan., facilities.

The market for these combis has been primarily for military aircraft and helicopters, Major says, but the company is pursuing potential airline business. It has orders to furnish units for the Bell/Augusta 609 civil tiltrotor. The company also produces in Wichita separate FDR and CVR units for the Gulfstream V.

The Penny & Giles multipurpose recorder will record for 120 minutes. The flight data recording function will accommodate parameters for up to 25 hours.

SFIM Industries

SFIM Industries, Groupe Sagem, provides a number of beacon-equipped flight recorders and video recording systems, as well as data acquisition and management units, data interface units, data loaders and related test equipment for commercial, business and small aircraft.

SFIM’s SSCVR (solid-state cockpit voice recorder) is suitable for all commercial airplanes and meets ARINC 757, TSO C 123 and ED 56 (A) standards. The system interfaces with the control panel and OMS-ARINC 624 and has a recording duration of two hours per channel, with four channels.

The SSFDR for commercial airplanes meets ARINC 747, TSO C 124 and ED 55 specifications. Recording rates are 64, 128 or 256 WD/second and durations are 64, 50 and 100 hours.

SFIM’s Mini-ESPAR 2, for small airplanes and helicopters, is a protected airborne data recorder incorporating transducers and acquisition functions. Recording time is up to 24 hours for parameters and up to one hour for audio. The 20-pound (9-kg) unit comes with three synchros and three frequencies with options of one or two mixed audio channels, and an ARINC 429 or Mil-Std-1553 serial bus or two pressure transducers.

Smiths Industries Aerospace

Smiths Industries Aerospace–headquartered in London with offices in Grand Rapids, Mich.–has a product line that includes separate CVR and FDR units and a combined option that weighs 7.2 pounds (3.3 kg), including the beacon. The audio capability has growth provisions for four-channel, 120-minute operation, and the unit can be configured as a data-only system.

FDR/CVR technology at Smiths is built

on the company’s military data recording expertise, with more than 4,000 solid-state recorders supplied in the last 10 years, the company says. Smiths produces CVR/FDR units for various U.S. military helicopters. It also makes integrated data acquisition recorders (IDARs) for the B-1 bomber.

Sony Precision Technology

Sony Precision Technology America Inc.’s SIR-1000 Series data recorders provide wide-band, multichannel recording and have digital readout displays. The company also provides CD analyzer products.

Sony’s SIR-1000W is a high-speed, wide-band digital data recorder that uses advanced intelligent tape (AIT) recording technology to collect multichannel analog and digital data, as well as digital video. The system can record and play back from two to 32 hours of high-fidelity analog data at frequency bandwidths up to 160KHz. Virtually any channel count and bandwidth may be configured through expansion modules and synchronization. Tape speed can be set at any of five ranges. In addition to the analog data channels, the SIR-100W is equipped with auxiliary channels that permit the simultaneous recording and playback of other kinds of information along with data.

British Aerospace

British Aerospace Systems and Equipment (BASE) offers the SCR500 family of cockpit voice and combined recorders, ground support equipment and cockpit control panels designed for use with BASE’s solid-state recorders.

For large aircraft, the SCR500-1620 combined recorder has dual redundancy, along with two hours of recording time, four-channel cockpit voice, and 25 hours of digital data. The SCR-630, and -600 combined flight data recorders (for civil aircraft and helicopters) with 30- or 60-minute CVRs also have 10-hour data recorders. The -1530 and -1560 models (for large helicopters) have a capacity of 25 hours for digital data, in addition to four channels and recording times of 30 minutes or one hour. The SCR500-030 and -120 CVS offer 30 and 120-minute recording.

Dukane Corp.

Dukane Corp.’s Seacom Division, in St. Charles, Ill., designs and produces high impact underwater locator beacons ("pingers") used to recover flight data and voice recorders involved in water accidents. The company’s DK120 and DK100 underwater acoustic locating beacons use low voltage battery technology that promises a six-year life. The beacons are designed to operate in water depths to 20,000 feet.

What Lies Ahead

Today, flight data recorders have far more capability than required by regulation. For example, up to 800 parameters are monitored on the Boeing 777; only 88 are mandated. And, beyond information for accident investigations, recorders can now provide data airlines can use for maintenance and flight operations purposes. Teledyne Controls touts its DFDAU as offering "the most advanced aircraft condition monitoring system available.

"Our system, besides providing required data for the digital FDR, also has a programmable part of the box. The customer can program this in conjunction with a ground data processing station and obtain performance data on engines and structures," says Steve McDonnell. "We can get trend data and potentially solve problems before they occur."

Meanwhile, with its IDARS, Smiths Industries combines in a single, line replaceable unit (LRU) the data and voice recording functions with the FDAU’s processing and analysis. The IDARS is modular and expandable, and it serves in a health and usage monitoring system (HUMS) capacity.

Regarding the future, recorder makers see an emerging need to record digital messages which are replacing voice messages both in pilot-to-air traffic control communications and in intra-airline communications. That technology is available, suppliers say. The next step would be video recording of certain cockpit displays that the pilot sees on the electronic flight instrument system (EFIS) or primary flight display (PFD).

"Accident investigators can no longer review the positions of knobs and dials after an incident, as these have been replaced with electronic displays," says Stephen Scolnik, marketing communications manager for Universal Avionics. "Video inputs could prove invaluable in evaluating the circumstances and data which the electronic displays presented to the pilot. So, video, too, could become another element stored in the CVR/FDRs of the future."

For more information, see www.honeywell.com; www.smithind-aerospace.com; www.uasc.com; www.L-3com.com; www.teledyne.com; www.sfim.com; www.sonypt.com; www.bae.com; www.pgaerospace.com; www.dukane.com, and www.avionica.com.

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