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Explosive Threats to Aviation (Historical Review)

This article looks back at the long history of explosive threats that the aviation industry has faced. Through this review we see that the motives have changed along with the explosives employed from simple dynamite bombs to highly sophistication improvised explosive devices (IED). As we move closer to the implementation of Third-Party K9 (3PK9) screening of cargo, it is important to understand that this threat is neither new or likely to dwindle in the future.

                          Boeing 247

                         Boeing 247

First Proven Act of Air Sabotage in Commercial Aviation

The first recorded explosive attack on the aviation industry was recorded on October 10, 1933. A Boeing 247 airliner operated by United Air Lines was on a transcontinental flight, originating in Newark, New Jersey to its final destination in Oakland, California. The three crew members and four passengers never arrived the flight crashed near Chesterton, Indiana. The investigation found that the crash was the result of an explosion somewhere in the baggage compartment in the rear of the aircraft. Nitroglycerine is believed to be the explosive material in the bomb. On November 16, 2017 the Federal Bureau of Investigation declassified 324 documents related to the investigation. Attach was suspected to be in connection with a Chicago gangland murder, but the case remains unsolved; no suspect was ever identified or charged in this incident.

          Wreckage of United Flight 629

          Wreckage of United Flight 629

United Airlines flight 629

On November 1, 1955 a Douglas DC-6B operated by United Airlines was on a transcontinental flight from New York, NY to Seattle, WA carrying 44 souls when it was attacked, killing all on-board. Investigators determined that John "Jack" Gilbert artfully concealed a bomb composed of Dynamite in a Christmas present for his mother. His motive for bombing the aircraft was to incite revenge on his mother for his childhood and to obtain a large life insurance payout. At the time of the attack there was no law against bombing an aircraft. As a result of this attack and the tragic loss of innocent lives, congress passed a bill which made the intentional bombing of a commercial airliner illegal. President Dwight D. Eisenhower signed the bill into law on July 14, 1956.  

                  Western Airlines Convair 240-1

                  Western Airlines Convair 240-1

Western airlines flight 39

The first suicide bombing in aviation history to place on-board Western Airlines Flight 39 on July 25, 1957. The Convair 240-1 was on a multi-stage flight from Minneapolis - Salt Lake City - Cedar City - Las Vegas - Los Angeles. A passenger named Saul Binstock flew from Burbank, CA to Las Vegas where he stayed inside of the airline's terminal till he boarded the returning flight from Las Vegas to Los Angeles. Soon after take-off Binstock locked himself in the aft lavatory and set off a bomb comprised of dynamite. The blast from the explosion killed Binstock and created a 6' x 7' hole in the fuselage. Despite the catastrophic damage to the aircraft the pilots managed to safely land the aircraft. Of the 16 people on-board the aircraft (13 passengers & 3 crew), the only fatality was Binstock.  


National Airlines flight 967

On November 16, 1959 a Douglas DC-7B carrying 36 passengers and 6 crew was traveling from Tampa, Florida to New Orleans when it crashed into the Gulf of Mexico. The investigation into the crash revealed some mysterious findings regarding passenger William Taylor. Taylor disappeared the day before the flight after he called his work telling them he was running late. The next time Taylor is reportedly seen is just prior to Flight 967; when he purchased $37,500 flight insurance policy. Though it is thought that Taylor died on the flight and his ex-wife received the policy payout; National Airlines has no record of a passenger with that name boarding the flight. The ticket that Taylor used to board the flight was issued to Robert Spears a native of Texas. Spears was a long time friend of Taylor and was visiting him just prior to the crash. Both individuals had extensive criminal backgrounds. Investigators believe that Taylor was trick by Spears to boarding the flight and carrying a piece of luggage that contained a bomb. When the plane crashed killing all on-board it was assumed that Spears had died on the flight. Spears wife could collect the $100,000 life insurance policy. After the plane was destroyed Spears vanished until he was arrested in Phoenix, Arizona, for the unlawful possession to Taylor's vehicle. At the time of Spears arrest authorities found dynamite and blasting caps in the vehicle, despite this evidence investigators were unable to conclusively link Spears to the plane's crash. The lack of physical evidence recovered from the plane made it impossible to prove the connection. As a result no charges were ever brought against Spears for the bombing of National Airlines Flight 967.   

            National Airlines Flight 2511 Wreckage

            National Airlines Flight 2511 Wreckage

National Airlines Flight 2511

On January 6, 1960 a Douglas DC-6B carrying 29 passengers and 5 crew enroute from New York City to Miami broke apart in flight and crashed in North Carolina. The resulting investigation found that the crash was caused by the detonation of a bomb comprised of dynamite around the 7th row of the aircraft. Investigators believe a passenger named Julian Frank committed suicide setting the device off. Frank was under investigation for fraud and embezzlement and had purchased life insurance policies worth $1,000,000 before the flight. Given the similarities to the National Airlines Flight 967 crash two months earlier; however others involved in the investigation suspected that Frank might have been unaware that he was carrying the device. As a result of the investigations findings no one was ever charged and the truth regarding both National Airlines Flights remain a mystery.  

Shattered wreckage of Continental Airlines Flight 11

Shattered wreckage of Continental Airlines Flight 11

Continental airlines flight 11

May 22, 1962 Continental Airlines Flight 11 a Boeing 707 carrying 37 passengers and 8 crewmembers took off from Chicago for stops in Kanas City and Los Angeles. The flight would never reach those destinations due to the detonation of a device comprised of dynamite placed in a towel container under the right rear lavatory washbasin. The effects of the blast caused the plane's tail to detach from the aircraft, pilots could not control the aircraft and the flight went down near Unionville, Missouri. Investigators blame the explosion on a passenger named Thomas Doty who had recently purchase a $300,000 life insurance policy and had an extensive criminal record.  

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Trans World Airlines Extortion Plot

On 7 March 1972 a person calling himself Gomez carried out an extortion plot following the labor disputes at the Trans World Airlines (TWA). Gomez warned that four bombs had been planted aboard TWA aircraft. Gomez stated that the devices would detonate over an 18-hour period, but he would provide the locations of the bomb's if he received $2,000,000.

TWA Flight 7

Gomez told authorities that the first device was aboard TWA Flight 7 a Boeing 707, that had just departed from JFK enroute to Los Angeles carrying 52 passengers and crew. TWA Flight 7 received notification of the threat 30 minutes after takeoff and immediately returned to JFK. Upon arrival the aircraft was searched and a briefcase was discovered in the cockpit containing 5lbs of C4 explosives set to detonate midflight. 

Federal Aviation Administration Officials were receiving a demonstration on the effectiveness of Detection Canines in another area of the Airport. In response to the event the two K9 quickly responded to the aircraft. K9 Brandy a trained Explosive Detection German Shephard detected the explosives in a flight bag located in the cockpit marked "Flight Crew - DO NOT DISTURB". As a result of Brandy's find authorities were able to disable the device 12 minutes prior to the timed device being activated. 

The extortionist called the TWA to arrange the payoff in Atlanta that afternoon. The TWA loaded the money onto a business jet and flew to Atlanta with the money. However the extortionist broke contact and the money was never paid. 

TWA Flight 57

The extortion plot against the TWA continued on March 8, 1972, when a bomb exploded on-board a TWA Boeing 707 that was parked at the Las Vegas, NV airport. On one was aboard the aircraft at the time the device detonated. The aircraft had arrive from New York seven hours prior and was searched before it departed, in flight, and after arrival. Even though the plane was under guard, someone was able to board the aircraft and place a device comprised of C4 into the aft portion of the cockpit or into the forward lavatory. The blast completely destroyed the Boeing 707. 

The extortion plot has a significant effect on TWA and the airline industry in general. Passengers, luggage, and cargo were screened meticulously like never before. Aircraft were heavily guarded as President Nixon ordered into immediate effect new airline security regulations. Nervous passengers cancelled flights, this had a significant financial impact on the entire industry.

Additionally, copycat bombers appeared placing explosives on two United Airlines Flights. Both devices were discovered before the were set to detonate. The first device was discovered on a flight from Seattle was comprised of dynamite and the second device discovered on a separate flight was comprised of plastic explosives concealed in two aerosol spray cans.  

American Airlines Flight 444

On November 15, 1979  a Boeing 777 operated by American Airlines carrying 72 passengers and 6 crewmembers enroute to Washington D.C from Chicago became a victim of Ted Kaczynski (AKA Unabomber). This was Kaczynski's first attack investigated by the FBI. 30 Minutes into the flight a mail bomb hidden inside a wooden box in the cargo hold ignited. The device produced a large amount of smoke but failed to detonate. Investigators found that a faulty timer is the only thing that prevented the bomb from destroying the plane. The pilots was able to successfully land at Washington-Dulles airport; with zero fatalities however, several passengers did have to receive treatment for smoke inhalation.

The Unabomber (Ted Kaczynski) continued his bombing attempts for 18 years before he was finally caught in 1996.   

United Airlines Cargo Explosion

On September 9, 1980 passengers were disembarking a Boeing 727 in Sacramento, California, when a small cardboard box in the aircrafts cargo hold detonated. The explosion injured two cargo handlers but, none of the passengers or crew were harmed. 

Pan Am 830.png

Pan American World Airways Flight 830

On August 11, 1982 a Boeing 747 operated by Pan AM was traveling from Tokyo to Honolulu, HI, when a bomb hidden under a seat cushion detonated. Killing a 16 year-old Japanese boy and injuring 15 other passengers. The explosion tore a hole in the floor and damaged the cabin ceiling along with the overhead bins. Despite the significant damage and chaos the pilots were able to make a safe emergency landing in Honolulu with no additional injuries. The attack was carryout by a terrorist organization known as the 15 May, the group was an offshoot of the Popular Front for the Liberation of Palestine - External Operations (PFLP-EO).  The attack was lead by Mohammed Rashid; who was arrested in Greece in 1988 received a 15 year prison sentence. Rashid was release from prison in 1996 after only serving eight years of his sentence. Rashid was convicted by the United States Government and sentenced to another seven year sentence in 2006. 

                     Cockpit section of Pan AM 103

                     Cockpit section of Pan AM 103

Pan American World Airways Flight 103

Pan AM Flight 103 a Boeing 747 departing from London bound for New York City was destroyed in the skies over Lockerbie, Scotland. The aircraft was demolished by 340 to 450 grams of Semtex a general-purpose plastic explosive containing RDX & PETN hidden inside a radio cassette player. The device was detonated in the forward cargo hold of the plane. The attacked killed all 243 passengers and 16 crewmembers along, with 11 people on the ground. The three-year investigation conducted jointly between the United Kingdom and United States; concluded that two Libyan intelligence officers were behind the plot, and both men were eventually turned over by the Libyan government in 1999. In 2001 one of the officers was convicted of the plot, the other was acquitted, and the Libyan government agreed to pay compensation for the attack. 

American Airlines Flight 63

                FBI's photo of Richard Reid's shoes.

                FBI's photo of Richard Reid's shoes.

On December 22, 2001 a Boeing 767 operated by American Airlines traveling from Paris to Miami became the setting for a terrorist plot carried out by radical Islamic terrorist Richard Reid. Reid was an Al-Qaeda operative from the UK attempting to continue the organization's attacks following the September 11, 2001 aircraft hijackings. As the flight was over the Atlantic Ocean, Reid attempted to detonate a bomb he had concealed in his shoes which contained 100 grams of explosives. The device contained two types of explosives TATP a peroxide based explosive and PETN which is structurally very similar to nitroglycerin. The device was strong enough to create a large hole in the fuselage and would have mostly resulted in a catastrophic event for the aircraft. When Reid attempted to detonate the device he was noticed by a flight attendant who tried to stop him, other passengers and attendants join in to subdue the suicide bomber. Pilots diverted the flight to Boston where Reid was arrested and sentence to life in prison. A second Terrorist named Saajid Badat was also arrested and convicted as Reid's conspirator. Badat was suppose to carry a similar shoe bomb onto a flight from Amsterdam to the United States but, backed out before the attempt. 

The investigation into Reid's shoe bomb found that the device failed to detonate due to the perspiration from his feet dampened the TATP and prevented it from igniting. 

2006 transatlantic aircraft Bombing plot

On August 9, 2006 British police arrested 24 people foiling an Al-Qaeda plot to detonate liquid explosive on seven aircraft traveling from the United Kingdom to the United States and Canada.  The plan was that each bomber would board the plane with all the necessary ingredient and equipment to carry out the attack. The bombers would construct the devices mid-flight and detonate them bring down the aircraft. 

2006 transatlantic plot.gif

Prior to the flight the bombers would take and remove the contents of plastic soft drink bottles. The bombers would use syringes so that they could conceal evidence of tampering. They would then replace the contents with hydrogen peroxide and a sugary drink powder. This would color the peroxide to resemble the proper color. A disposable camera would be disassembled and one of the batteries modified to carry a second high explosive. Once on-board the aircraft the bomber would remove the modified battery placing it on the side of the bottle. The battery would be connect to the cameras flash component. The energy from the flash would setoff the smaller charge which would then detonate the larger charge. Of the original 24 personnel arrested three men were found guilty of conspiracy to kill by blowing up aircraft and four others guilty of conspiracy to murder.  

Northwest Airlines Flight 253

Northwest Airlines Flight 253.jpg

On December 25, 2009 an Airbus A330 operated by Northwest Airlines traveling from Amsterdam to Detroit was the target of a failed Al-Qaeda bombing attempt. A Nigerian National Umar Farouk Abdulmutallab unsuccessfully attempted to detonate a explosive device concealed in his underwear. The substance that Abdulmutallab attempted to detonate was more than 80 grams of PETN and TATP. The device was sewn into his underwear and he used a syringe filled with chemicals to attempt to ignite the explosives. The main charge did not detonate, however there was a small explosion and a fire. Abdulmutallab suffered first and second degree burns to his hands and second degree burns to his thighs and genitalia. 

2010 Transatlantic explosives plot

On October 29, 2010, two packages, each containing a bomb consisting of 300 to 400 grams of plastic explosives and a detonating mechanism, were found on separate cargo planes. The bombs were discovered as a result of intelligence received from Saudi Arabia's security chief. They were bound from Yemen to the United States, and were discovered at en route stop-overs, one at East Midlands Airport in the UK and one in Dubai in the United Arab Emirates.

                          Toner Cartridge IED

                          Toner Cartridge IED

Each package contained a Hewlett-Packard HP LaserJet P2055 desktop laser printer. Inside each printer's toner cartridge was a complex device filled with pentaerythritol tetranitrate (PETN). The bomb found in the UK contained 400 grams of PETN. The device found in Dubai contained 300 grams of PETN. The PETN main charges were connected to a cell phone triggers when activated the phone battery would send power through a thin filament inside a syringe containing 5 grams of lead azide (Pb(N3)2) is a highly sensitive an inorganic compound. Lead azide is usually handled and stored under water in insulated rubber containers. The compound will detonate after a fall of 6 inches or in the presence of a static discharge of only 7 millijoules. Once the lead azide heated up it would ignite resulting in the detonation of the PETN. 

The devices were constructed in such a manner that the printer components would appear to be correct if they were x-rayed. The phones features like the display which are not relevant to the alarm timer function were removed in order to extend the devices battery life. The devices were not able to receive any communication with the SIM cards being removed. This also increase the battery life of the phones.

The device identified in the UK was inadvertently disarmed by Scotland Yard explosive officers, when they removed the printer cartridge from the printer during their examination that morning. This was approximately three hours prior to the designated time for the Improvise Explosive Device (IED) to detonate. The officers were not aware at the time that the printer was an a bomb.

One week later, al-Qaeda in the Arabian Peninsula (AQAP) took responsibility for the plot, and for the crash of UPS Airlines Flight 6. U.S. and British authorities believed Anwar al-Awlaki of AQAP was behind the bombing attempts, and that the bombs were most likely constructed by AQAP's main explosives expert, Ibrahim Hassan al-Asiri. The bombs were probably designed to detonate mid-air, with the intention of destroying both planes over Chicago or another city in the U.S. Each bomb had already been transported on passenger and cargo planes at the time of discovery.