Air Cargo: A Higher Global Risk Profile

Air Safety Week, Dec 18, 2000

"All types of accidents occur more frequently in cargo operations."

The accident rate of air cargo operations in disproportionally high compared to passenger operations, with the exception of those cargo carriers in the U.S. specializing in overnight express package delivery.

Companies such as Federal Express [FDX] and United Parcel Service [UPS] have achieved a safety record comparable to that of passenger operations worldwide, as measured by the accident rate per million flights. However, when all types of U.S. cargo operations are factored in, the accident rate for cargo operations in North America is about five times higher than for the region's passenger operators. Cargo operations in Europe compare favorably to the accident rate for European passenger flights but, again, this second bit of good news stands out against a grim background.

A recent study of the safety performance of air cargo operations by the National Aerospace Laboratory (NLR) of the Netherlands found the high accident rate among ad-hoc (unscheduled) air cargo operators in the U.S. "disturbing," and it characterized as "dramatically unsafe" cargo operations in Africa and South America.

The study focused on Western-built jets and divided cargo operations into four categories:

1. Major operators: companies operating both passenger and cargo aircraft, using the same maintenance and training facilities, such as KLM, Lufthansa and Air France.

2. Integrators: Large parcel delivery operators such as FedEx, UPS and DHL.

3. Supplemental air carriers: for purposes of the NLR study, these were defined as commuter airlines and their counterparts in the cargo world utilizing smaller and mostly turboprop aircraft.

4. Ad-hoc operators: these were defined as carriers operating a very high percentage of unscheduled flights, including both cargo flights and holiday/vacation passenger charter flights.

Risky Business

The study looked at nearly 30 years of data (1970-1999), some 2,000 operators and more than 460 million flights. Further, the study focused on aircraft with a maximum takeoff weight of more than 12,500 pounds. Only Western- built aircraft were considered; business jets were eliminated from the study database, and hull losses that occurred while the aircraft was on the ground with no payload onboard likewise were excluded.

The results in brief:

Ad-hoc carriers have a particularly high-risk profile - the accident rate is nearly seven times higher than the majors' record for passenger operations.

The integrators "show a very low accident rate" according to the study. However, the integrator business "is almost exclusively limited to U.S.," according to the NRL study.

A look by region spotlights Asia, South America and especially Africa as problem areas with respect to air cargo operations.

Further granulating accident rates in the various regions by type of operation shows that there is a much greater variation in safety between cargo and passenger operations in the U.S. than in Europe.

While the safety record of U.S. integrators is good, the study characterized the high accident rate among ad-hoc U.S. operators as "disturbing."

Cargo operations in Africa and South America are "dramatically unsafe." Further, The ad-hoc passenger (charter) accident rate in Asia, at 10 accidents per million flights, "is also reason for great concern."

The distribution by cause (loss of control, engine failure, overrun, etc.) was remarkably similar between passenger and cargo accidents. In both segments "collisions with ground" comprised fully a quarter of the accidents. "The fact that the relative distribution of accident types is nearly the same for passenger and cargo operations leads to the conclusion that all types of accidents occur more frequently in cargo operations," the study asserted (emphasis in original).

Risk Factors

What are the underlying causes? The authors of the NRL study cited a number of safety-related characteristics of cargo operations:

Night flying. More than half of cargo movements take place at night, compared to just a fifth of passenger flights. The attendant sleep disruption, restricted visibility and loss of depth perception and visual contrast at night all contribute to a fourfold increase in the probability of an accident at night.

Pilot turnover. The high percent of nighttime cargo operations contributes to personnel turnover. Young pilots look to the cargo segment to build up time to enter the world of the major carriers. Older pilots sometimes find employment in the cargo segment. "This can lead to flight crews with very large differences in age between captain and co-pilot, which could be a problem as far as crew resource management (CRM) is concerned," the study intimated.

Older planes. The average age of cargo aircraft has increased from 14 to 22 years, while the average age of passenger aircraft has held roughly constant at 10 years. In other words, the passenger aircraft fleet is being renewed, while the cargo fleet continues to grow older. Maintenance of aircraft becomes a greater issue, particularly among the less financially healthy ad-hoc carriers. Reduced maintenance can erode the margins of safety. Also, there are fewer cargo planes equipped with the latest avionics, flight displays, and high-bypass engines certificated to higher standards. While almost a third of all passenger flights are now conducted with these aircraft, the number of cargo flights conducted by such aircraft is negligible.