When the representative of a Peruvian firm arrived to pick up his package, Hector Orlansky, the president of Miami-based Orler Courier, watched nervously, waiting for the trap to spring.

The man signed for the two hollowed-out books containing 10 pounds of concealed cocaine. Instantly, federal agents from U.S. Customs and the Drug Enforcement Administration sprang forward, weapons drawn and trained to the man's head.I had to make the guy sign (for the shipment), Mr. Orlansky says. And being in Miami I was pretty scared. But if I have to do it, I'll do it again.

That drama, played out last year in Miami, coupled with Mr. Orlansky's willingness to replay it if necessary, underscored the new facts of life at a convention in Phoenix recently of the Air Courier Conference Association.

Increasingly, air courier companies are concerned about their unwitting participation in drug running and contraband transport. Such smuggling is still measured in pounds, not tons. And the air couriers have nowhere near the recently highlighted problems faced by those in marine container transportation.

But some of the same features that attract business customers - fast, efficient, overnight or second-day delivery - also have attracted criminals to the services. Too often for the tastes of the Air Courier Conference Association, when illegal drugs absolutely, positively have to get there, criminals are viewing air couriers as the new mules of the drug trade.

Air express companies are deathly afraid of developing a reputation, says Steven Waller, senior vice president and chief operating officer at DHL Worldwide and chairman of the international committee of the Air Couriers Conference Association, a Reston, Va.-based trade group.

Most companies work closely with the authorities on the problem, he said. I think U.S. Customs in particular has recognized the responsibility of the air express guys.

According to U.S. Customs, two pounds of heroin was seized in express shipments nationally in the year ended Oct. 1, 1987, compared with total heroin seizures of 639 pounds. Twenty-five pounds of cocaine was seized in express shipments during the same period compared with 88,000 pounds seized nationally. Marijuana confiscation was a minimal percentage of total seizures.

Vince Dantone, program officer in the U.S. Customs office of Inspection and Control, says drug seizures in express shipments are very low relative to the number of packages they handle. And it's not for lack of trying, he says.

Mr. Dantone cites a recent U.S. Customs effort to stop a stream of heroin entering by mail from Hong Kong. As a precaution the agency inspected express shipments as well. Of nearly 4,000 express packages examined during a single week, not one was found to contain drugs.

Even so, courier companies say, they are uncomfortable with even a single seizure in their system and have increased their vigilence.

Strong incentives also exist for keeping on top of the problem, says Bruce Friedman, a co-owner of Canadex Ltd., a New York-based courier linking the United States and Canada. If you develop a bad performance record with Customs, your shipments will be regularly delayed and this will hurt business. You also are liable for fines of up to $500 per ounce of marijuana and $1,000 per ounce of cocaine or heroin that is discovered.

Customs also is developing rules that would require express companies to sign security pledges and participate in programs in return for expedited handling of international express shipments.

One factor companies believe keeps their services from being used extensively by drugrunners is the close scrutiny common in the industry. Each package is checked, sorted and given a specific air bill as a matter of course. Air express is more closely controlled, Mr. Waller says. That's why (drug runners) use passengers and suitcases.

Couriers say their first line of defense is to keep a close eye on what is shipped. Since most of the packages contain documents, unusual items stand out.

Roy Friedman, co-owner of Canadex, says warning signs include nebulous commodity descriptions, suspicious countries of origin, irregular packaging and insufficient address information.

The air transport system itself also provides certain safeguards. Santiago Szachniuk, president of Miami-based Air Facility, a wholesale courier company with business in Latin America, says his company works with retail courier companies to ensure that they know what they are sending. But also it relies on the air carriers which have their own stringent inspection process.

Express companies say they also pay close attention to new customers and non-corporate accounts and often open packages from these clients. Dick Temple, managing director of London-based Direct Link Courier, says most of his customers are blue-chip companies. The only time the company had trouble, he says, was when it accepted a shipment from someone walking in off the street.

The hardest shipments to detect, says Norman Brodsky, chief executive of New York-based Citipostal, involve contraband sent company to company.

Express companies also say they watch for unusual behavior. In addition to over-eager customers, there may be other clues. Mr. Brodsky of Citipostal says these include strange calls at unusual hours, customers that don't care about the price or those that pay for c.o.d. shipments in cash.

Most times we refuse to do calls of that nature, he says. But if it slips through we turn it over to the DEA (Drug Enforcement Administration).

Courier companies add that U.S. Customs is looking over their shoulder. Whenever a non-corporate shipment comes from South or Central America, Customs routinely checks the identity of the consignee and usually arranges for an inspection, says Bio Gabriel, deputy managing director of North America for Aramex.