Over the last decade, business aviation safety has improved immensely. During that time, regulators have attempted to reduce accidents by introducing a variety of equipment, avionics, and procedural requirements.

Has safety improved because of these requirements or have they been a financial, maintenance, and procedural drain not justified by the results they've produced? Like most complex things in life, the answers aren't always clear and depend in many cases on the specifics of the situation.

For example, although the safety record of fractional operators since 1996 has been excellent, the FAA saw fit to require them to fly under essentially the same safety requirements that apply to air taxis (Federal Aviation Regulations Part 135) or meet an entirely new set of FARs-Part 91, Subpart K.

Has the accident rate changed significantly since Subpart K took effect in 2003? Not really. To date, there have been no fatal accidents involving fractionals, and their accident rate (the number of incidents per 100,000 hours) last year was better than that for all other segments of turbine-powered business aviation.

On the other hand, there's no question that systems and procedures introduced to business aviation over the last 10 years have helped investigators better determine the probable causes of accidents, as well as find accident locations and survivors more quickly. A case in point is the 2004 mandate requiring emergency locator transmitters (ELTs) on all jet aircraft.

The revised rule resulted from an act of Congress in response to the fatal crash of a Learjet 35 business jet in 1996 at Lebanon Municipal Airport in New Hampshire. Searchers gave up trying to locate the wreckage and it wasn't until two years after the crash that it was found by chance. After an airplane crashes, ELTs emit a signal that can be heard by passing aircraft and is also monitored by satellites. The signal leads search-and-rescue personnel to the downed aircraft.

Congress was also responsible for the 1974 mandate for airlines to be equipped with Ground Proximity Warning Systems (GPWS), which provide pilots with alerts if they come too close to terrain. In 1996, a technical upgrade was made and the enhanced devices are called Terrain Awareness and Warning Systems (TAWS).

There have been no accidents of the kind that TAWS is designed to prevent since the equipment was installed on all airliners and on air taxi and private business jets configured for six or more passengers.

Interestingly, unless the rule is changed, the TAWS requirement won't apply to the new segment of very light jets, because most VLJs will have fewer than six passenger seats. Also, there are no requirements for TAWS on turbine-powered helicopters.

While TAWS addresses the issue of airplanes flying into terrain, Traffic Alert and Collision Avoidance Systems (TCAS) are intended to help prevent airplanes from hitting each other—both on the ground and in the air. Since Jan. 1, 1996, TCAS has been required on air-taxi (charter) jets configured for 10 or more passenger seats. But TCAS isn't required in most privately owned jets.

You might assume that the stiffer the operational requirements, the safer the operations, and some evidence does support that conclusion. For instance, statistics indicate that the major airlines have the lowest accident rate of all segments, but that isn't the case when you compare accidents for business jets flown under the more restrictive air-taxi requirements with those flown privately by salaried pilots.

Aviation experts surmise that because air taxi jets fly shorter and more frequent flights than private jets, they are more frequently exposed to the two most dangerous events-takeoffs and landings. However, the takeoff and landing frequency for air taxis is similar to that for fractional operators, yet the latter have fewer incidents and accidents. It's a conundrum.

Runway Overruns Abundant

Business airplane accidents involving icing, loss of control, and fouled approaches in bad weather have caused the most loss of life over the past 10 years, according to safety analyst Robert E. Breiling of Boca Raton, Fla.

But one of the most numerous mishaps for private and commercial aircraft is the landing or aborted takeoff overrun. Last year alone saw 44 runway overruns involving large aircraft, according to the International Federation of Air Line Pilots' Associations. The data served to underscore the group's crusade to get runway-end safety areas or arrester beds installed at all major airports worldwide.

Although many runway overruns aren't investigated by the National Transportation Safety Board (NTSB) because they don't cause serious damage or injury, there have been some spectacular ones that have caused fatalities and resulted in new requirements for operators of both aircraft and airports.

The widely publicized February 2005 crash of a Bombardier Challenger business jet when it overran a runway after an aborted takeoff at Teterboro Airport in New Jersey got the ball rolling on the FAA's investigation into improper and allegedly illegal charter operations. And the overrun last December of a Southwest Airlines Boeing 737 at Chicago Midway Airport led to a controversial proposal for a new runway calculation procedure for airlines, air taxis, and fractionals.

These and other runway overruns have led the FAA to take action to help prevent damage and injuries from such incidents. Airports that serve the airlines are now required to construct 1,000-foot safety areas or barriers at the ends of their main runways, where possible. Some airports have had to shorten the usable length of one or more of their runways to accommodate safety areas. However, no requirement exists for safety overruns or barriers at most general aviation airports used by corporate jets.

Designed for runways that don't have enough space for 1,000-foot-long safety areas, Engineered Materials Arresting Systems (EMAS) are being installed at several airports. To date, EMAS has been credited with preventing injury and aircraft damage on four occasions, including to a Dassault Falcon 900 business jet when it overran the runway on July 17 at South Carolina's Greenville Downtown Airport.

What's Old Is New Again

Since its inception in 1967, the NTSB has investigated more than 124,000 aviation accidents and issued more than 5,000 aviation recommendations, mostly to the FAA. Since 1990, the NTSB has highlighted its most urgent issues on its "Most Wanted" list of safety improvements.

The Safety Board, however, has no regulatory authority and the FAA is under no requirement to adopt its recommendations. Nevertheless, the agency has acted favorably on more than 84 percent of them. Still, some in Congress don't believe that's a high enough percentage and have introduced an amendment to the NTSB reauthorization bill "to make the FAA explain why the Safety Board's Most Wanted recommendations have not been implemented."

Of the 16 percent of recommendations not enacted, many were initially published 10 or more years ago and several have been reiterated by the NTSB as new accident investigations raise old issues that have not been resolved, in the Safety Board's opinion.

Two recommendations have remained on the NTSB's Most Wanted list since its inception nearly 17 years ago: stopping runway/taxiway incursions (more than one airplane simultaneously on the active runway) and reducing dangers to aircraft from icing. Both of these items have been restated several times over the years because of continuing accidents or incidents of these types.

According to an NTSB statement late last year, "Although the FAA completed action on a number of objectives to make ground operation of aircraft safer, these incidents continue to occur with alarming frequency."

Said the NTSB recently: "The FAA's anti-incursion system provides warnings to air traffic controllers, but not to flight crews, a fact that reduces the time that pilots have to react to an impending incursion." The Safety Board has issued 100 recommendations regarding runway incursions since 1983.

The NTSB's recommendations and statements notwithstanding, however, the number of incursions has been steadily declining, according to FAA figures. Agency statistics show that there were 383 incursions in 2001 and 324 last year.

In 1997, as a direct result of the crash of TWA Flight 800 over New York's Long Island Sound a year earlier, the NTSB added to its Most Wanted list the prevention of explosive mixtures in transport aircraft fuel tanks. The Safety Board currently describes the FAA's action on this recommendation as "acceptable, progressing slowly."

Most Wanted recommendations for which the NTSB considers the FAA's response as acceptable include reducing accidents from the turbulence created by the wake of large jets (added in 1995 and removed in 1998), improving regional airline safety (added in 1995 and removed in 1996) and pilot safety background checks (added in 1996 and removed in 1998).

Voice Recorders Not Enough?

Flight data recorders (FDRs), required on all airliners but not yet on all business jets, have improved—both in the quality of their structure and the quantity of their data—as the result of accident investigations from 1996 to 2005 and constant prodding by the NTSB. But the Safety Board is disappointed that cockpit voice recorders (which record voices, instrument alerts, and other sounds in the cockpit) aren't required in all jet airplanes and it is unsatisfied with the quality of cockpit voice recorders (CVRs).

After several business jet accidents, the Safety Board expressed frustration over the fact that a CVR was either not required or failed to operate properly. For example, during its investigation into a May 9, 2005 Sabreliner business jet accident in which a bird strike was implicated, the Safety Board said the CVR recording "was of such poor quality it was useless for accident investigation purposes."

The NTSB also decried the lack of recorders or the so-called "black boxes" (which are actually painted a bright orange to make them easier to spot) on a Learjet that was involved in a fatal crash on Dec. 23, 2003. The airplane was equipped with neither a CVR nor an FDR and federal regulations didn't require them. "This is another example of where a recording device-whether a voice recorder, data recorder, or a video recorder-would have greatly helped investigators determine what happened," the Safety Board said. "An opportunity to improve aviation safety was lost here."

The lack of possibly important data, because the CVRs weren't working, was specifically referred to in the investigations of the Oct. 9, 1999 incident in which an Amway Dassault Falcon 900B experienced a series of serious pitch oscillations. The same issue arose with the May 21, 2000, fatal accident of an Executive Airlines twin turboprop that apparently suffered fuel starvation.

The NTSB also believes current requirements for retaining recorded cockpit voice recorder information don't go far enough in ensuring that pertinent data is available following accidents or incidents. Because of this longstanding concern, the Safety Board in 2002 asked the FAA to require pilots to deactivate the CVR immediately after an incident or accident (to be sure the data is retained) and to require a functional check of the device before each flight of the day. The FAA has yet to propose such a requirement.

In February last year, partly in response to the NTSB's urgings, the FAA did propose rules that would improve the quality and quantity of information from CVRs and FDRs.

Six years ago, the Safety Board recommended that the FAA require cockpit video recorders, instead of flight data recorders, in smaller turbine-powered aircraft used in air taxi operations. And about three years ago, the Safety Board added to its Most Wanted list a requirement for cockpit video recorders on all transport aircraft. To date, these recommendations have produced what the board called an "unacceptable response by the FAA."

Human Factors Still Dominate

Clearly, some recent rules, procedures, and systems have helped to prevent accidents, but the NTSB has for many years determined that the flight crew is at fault in more than 75 percent of accidents. This would seem to indicate that pilots always have the ability (fortunately or unfortunately, depending on your point of view) to ignore, overcome, or bypass systems, rules, and procedures designed to prevent accidents. As long as pilots make the final decisions in the cockpit, there will likely never be a system, rule, or procedure that is 100 percent foolproof.