Quite simply, prior to 9/11 checked baggage screening didn’t exist. Well, let me qualify that little bit, we did have this level of screening for certain international flights known as positive passenger bag match but there was no mechanism in place to consistently and routinely, for every flight, see what is inside the baggage that is going into the cargo hold.
Pretty much at any given point in time anyone could’ve put a bomb in their bag and no screening would have taken place as it was passed to the ticket agent, to the baggage handler and eventually loaded on the plane. It is actually astonishing to me that we did not have the bombing of a commercial aircraft throughout the 1990s. It is like leaving the front door of your house open with all of the families money, computers, jewelry and other valuables sitting just inside the foyer. We did everything short of putting a sign out saying “to blow up plane, just make sure its in your checked bag.”
We had not learned any lessons from the past – well, maybe we learned them but didn’t do anything about them. Over 500 people died in the 1980s alone from bombs place in checked baggage, including many Americans. Most notably was the bombing of Pan Am 103 over Lockerbie, Scotland in 1988 and the bombing of Air India Flight 182 just off the Irish coast in 1985. Shortly after bombing of Air India, Canada implemented the screening of checked bags by x-ray and other devices. England did so after the bombing of Pan Am. The United States did not.
The International Civil Aviation Organization had mandated the practice of positive passenger bag match (PPBM) for international flights. PPBM requires the airline to ensure that every piece of luggage loaded onto the aircraft has a passenger associated with it in the cabin. This does absolutely nothing to prevent a suicide bombing but, it can prevent bombings when the bomber didn’t want to die with his device. However, the investigation on the Pan Am bombing showed that not only were the bags not matched to the passengers in that flight but that this was a security process that was routinely ignored by the airlines.
In fact, PPBM was in place on 9/11 but only applied to passengers (even on domestic flights) who were flagged for secondary screening.
The United States would not move to the actual, physical and mechanical screening of checked baggage until after the passage of the Aviation and Transportation Security Act of 2001, two months after 9/11.
I even remember my days as the assistant security director at Denver International Airport, when people would ask me about that airports notorious baggage system and wonder where the bags were screened. I would shrug my shoulders and basically say: ‘underground’. Considering I had been at the airport for many years, even before it opened. I knew every square-foot of that place, and I knew that those bags were never screened, but that was not something I wanted to share publicly.
We did come close to screening checked bags after TWA 800 crashed off Long Island in July 1996. Explosive detection systems and explosive trace detectors were deployed to the airports, but they were put near screening checkpoints and so rarely used as to be ineffective.
After 9/11, by legislation the industry begin the implementation of Explosive Detection Systems and Explosive Trace Detection, plus Canine or Physical Inspection to the checked baggage process. The implementation took much longer than the December 31, 2002 deadline that Congress had mandated. TSA stated that they still met the deadline but that was by changing the definition of screening to include positive passenger bag match process, not by actually deploying the hundreds of machines throughout the airports. The industry simply could not build these machines fast enough so full implementation would take the better part of a decade.
Today, all checked bags are screened using explosive detection systems, or trace detection or some other form of screening. EDS systems are medical-grade Cat Scans that work by first x-raying a bag, then if there is an anomaly it sends it to the secondary section where it begins to “slice and dice” the imagery while the software conducts an assessment. If the software cannot clear the bag it is sent on to TSA personnel for additional screening.
Explosive Trace Detection is much slower but works nonetheless. ETD’s take a sampling of residue from the surface of the bag. It is then placed into a machine and heated up until it breaks down into it’s basic chemical components. These components are then analyzed by the software and compared with elements inheritor an explosive device.
Many EDS systems today are what are known as in-line. The machines are installed in-line with the baggage handling system and the vast majority of the screening process is conducted by automation. In smaller airports, you will see these machines sitting in the lobby. These are the airports where you are required to take your bag, after checking it in at the ticket counter, to drop off with a TSA screener who then screens it, and sends it off to the airline baggage handlers.
Prior to 9/11 with the exception of occasionally checking to be sure that a bag and a passenger match on a particular flight there really was no screening of checked bags. Now, billions and billions of dollars in machine acquisition and infrastructure remodeling the luggage that you check is now being checked before being placed on your plane. Here, we clearly are safer.