In February, a security breach in Antwerp, Belgium led to one of the biggest diamond heists in recent history. Under the cover of darkness, eight gunman in hooded police clothing gained access through an airport perimeter fence and drove onto the tarmac in two black vehicles with flashing blue police lights. With great speed and precision, the heavily armed thieves sorted through and removed packages from the cargo hold of a parked Helvetic Airways aircraft, loaded them in their vehicles and made a high speed getaway.

Preliminary speculation is that the thieves had inside information or assistance, much like the infamous Lufthansa Heist of 1978 at John F. Kennedy Airport in New York. Aided by the knowledge of an airport employee, members of the Lucchese crime family were able to steal in excess of six million dollars in untraceable U.S. currency and jewels from a temporary holding vault on the airport property. Insider knowledge and assistance was central to that crime’s success.

In response to the 9/11 hijackings, the nation’s aviation-security strategy shifted toward the external threat of passengers with malicious or terrorist intentions. But despite recommendations and concerns stated by members of the 9/11 Commission and aviation security experts, comparatively little attention has been given to the possibility of an inside job. This threat could come from any airline or airport employee with access to restricted areas within the airfield. This includes pilots, flight attendants, maintenance personnel, aircraft refuelers, cleaning crews, baggage handlers, food-service personnel and general airport workers.

If insider assistance was a factor in the Antwerp caper, does this highlight a gaping hole in security and the need to address the vulnerability that airport employees are for airport security? While the motive here was robbery, the concern is that not only criminals but terrorists may turn their attention to these security weaknesses. Terrorists in particular have proven to be patient and innovative at exploring other avenues to carry out their plans. Aviation-security experts and government officials strongly believe that this is the Achilles’ heel of the industry and where the next terrorist event will originate.

Pilots and flight attendants are intimately familiar with TSA security-screening procedures and have unrestricted access to the interior of an aircraft. They are extremely knowledgeable about their work environment and could easily conceal any illicit intentions. Although most pilots and flight attendants go through the same screening process as passengers, they are not held to the same stringent standards. With the exception of guns, knives and explosives, crews are at liberty to carry almost anything else on board an aircraft. These security requirements are an outright invitation for crew to smuggle contraband aboard an aircraft. Combined with the potential for terrorists to manipulate, coerce or incentivize an employee to do their bidding or work in concert with passenger co-conspirators, these possibilities pose a serious security threat to airliners.

Ground crews are largely unseen by the general public. But in much the same way as flight crews, they have intimate knowledge about their work environment. They also have unrestricted access to the exterior and interior of aircraft. Despite this access, these employees are not subject to the same security screenings as passengers and most flight crews.

Ground-crew employees usually access the inner workings of the airport through an employee entrance. This entrance should have a guard present and is accessed by a key, coded lock, biometric device, or other door-locking mechanism. It is not considered a screening checkpoint because its only purpose is to restrict access to unauthorized personnel—not to inspect employees or their belongings. Once inside, however, these individuals are given largely unfettered access to the airport property. They, like flight crews, know the inner workings of the airport and its security weaknesses.

The overwhelming majority of airport and airline employees are good, hardworking Americans. They harbor no ill will or intentions to cause harm to this country or to any person. In fact, they are extremely dedicated, professional and take great pride in their work. More often than not, they are the last line of defense in preventing a terrorist event. Yet the current strategy to combat the insider threat is insufficient.

A better solution would adopt a 100 percent screening program for all aviation employees. The infrastructure already exists for this increased level of security. The safe operation of commercial aircraft in the skies over the United States is critically important to our economy, national security and the psyche of the American people.

Steven Goff is a Naval Reserve aviator and commercial airline pilot. He is currently pursuing a master's degree in National Security and Strategic Studies from the U. S. Naval War College in Newport, RI. The views expressed are entirely his own.