Fireflash Disaster[]
Fireflash 3 prior to its disappearance.
The hypersonic airliner Fireflash 3 takes off from London International Airport as per usual, but later sends out a mayday, reporting losing height rapidly and reporting their position as TS757/AR436. London Airport sends out the Air Sea Rescue squad who fail to find any trace of the craft at its last reported position. The crash makes headlines, and the Air Ministry has the entire Fireflash fleet grounded until further notice. Meanwhile in Thunderbird 5, Alan Tracy realizes that Fireflash 3's last reported position was incorrect, more than 50 miles out, explaining the inability to locate the downed craft.
Patterson, a technician of the Fireflash division, tests the Fireflash craft, but everything checks out, so a test flight is launched the next day. All goes well, until the craft approaches the last position reported by Fireflash 3. The EPU (Elevator Power Unit) reads zero despite still being 150,000 ft. in the sky, and all the instruments start going haywire. Fireflash then sends out a distress call to London Airport, reporting mechanical problems, and eventually losing all contact once it reaches the exact position where Fireflash 3 disappeared. The pilots are then unable to control the craft as it dives towards the Atlantic, smashing into the water, but still in one piece. The pilots desperately try to escape the flight deck, but the escape door jams, leaving them trapped inside as Fireflash sinks beneath the surface of the water. An unidentified man (who parachuted from the undercarriage of the Fireflash prior to it sinking,) is then picked up by an EJ2 Jet; it was sabotage.
Off Course[]
The saboteur's aircraft (an EJ2 Jet).
Alan calculates that the sunken Fireflash's reported position was again off by approx. 180 miles northwest of position TS749/AP428. Thunderbird 2 is then dispatched to the position given by Thunderbird 5, and Brains calculates that the aircraft's mechanical failure could've prevented the crew from escaping, meaning the crew is trapped in the cockpit at the bottom of the sea. Meanwhile, on the sea bed, the crew desperately try to call for help, but to no avail. Thunderbird 4 is launched to explore the sea bed for Fireflash, and Gordon Tracy makes contact with the crew. He then uses Thunderbird 4 to cut off the heavy engines holding Fireflash down. Fireflash then floats to the surface, when the control panel suddenly bursts into flames, meaning Gordon must work fast. The crew is freed, and Fireflash erupts in a massive explosion. Fortunately, everyone makes it out ok.
Fireflash on the sea bed
Following the disaster, the airforce commanders convene for a second meeting. Thanks to Brain's information and the testimony of the crew members, they now know that the trouble originated from the craft's Elevator Power Unit (EPU) system in the starboard wing. However, both of the lost Fireflash showed no sign of damage or trouble before taking off. This means that the problem when the craft is airborne. The same thought crosses Jeff's mind, which prompts a suggestion from Virgil. Agreeing to his sons proposition, Jeff and Tin-Tin draft a letter to London Airport with a suggestion. International Rescue offer to test the Fireflash themselves with Scott at the helm. Meanwhile, Gordon and Virgil will fly alongside in Thunderbird 2 to monitor Fireflash and intervene if necessary.
Operation Crash Dive[]
Commander Norman immediately approves the operation. Knowing that secrecy will be vital to the operation, he orders the airport to be secured, air traffic cleared and asks Captain Hanson to serve as Scott's co-pilot. Hanson jumps at the opportunity to help International Rescue, wanting to repay them for saving his life in Trapped in the Sky. Virgil, Scott and Gordon arrive at London Airport at 12:00. Thunderbird 2 is carrying Thunderbird 4, the Diving Escape Bell, the laser beam cutter and boarding gear. Meanwhile, Fireflash will switch to open contact so that they can remain in contact with Thunderbird 2, Thunderbird 5 and the London Airport Control Tower.
Not long afterwards, the operation begins. Scott and Hanson take off without issue and soon approach the "crash zone". A few moments later, Virgil takes off in pursuit. Scott then radios Alan, asking to confirm his position, giving his coordinates LS749/AP428. However, Alan tells his brother that the planes auto-locator is giving off a wrong reading and that the Fireflash is actually 20 miles northwest of that position. With a fault detected, Alan relays the Fireflashs position to Virgil, whilst Hanson reports the error to the Control Tower.
Suddenly, without any prompting, the Fireflash veers off course. Hanson has just enough time to report a problem with the EPU before the radio dies. A moment later, the plane pitches down and starts to dive towards the ocean. Using his mobile control system, Scott is able to maintain contact with Thunderbirds 2 and 5. With Hanson estimating that they have fifteen minutes before they hit the water, Gordon gets ready to board the Fireflash and inspect the plane for damage. Gordon is able to board without issue, but not before spotting somebody who should not be there.
Not long afterwards, the mystery is finally solved when Gordon finds a large wire coupling that has been crudely cut in half. He has just enough time to report his discovery, before the saboteur opens fire upon him. A short scuffle breaks out between the International Rescue agent and the villain, all the while the Fireflash continues its sharp descent towards the ocean. The saboteur quickly notices that the undercarriage hatch is still open. Gordon advises him not to jump saying that he'd never survive the jump. Ignoring him, the murderer makes a break for it anyway. Gordon opens fire once again and the man either jumps or falls out of the hatch, never to be seen again.
As Fireflash nears the water, Scott tells Gordon to fix the broken coupling but Gordon tells him it can't be done in time. Realising his only option is to recreate the circuit, Gordon grabs the wires and forces them together, giving control back to Fireflash. Thanks to this quick thinking, Scott and Hanson are able to safely return the Fireflash to London Airport and the Tracy boys head for home.
Some time later, the family is watching a news report on the incident. The reporter reveals that the saboteur was a member of an international terrorist group bent on aircraft espionage. Thanks to International Rescues efforts the gang have been uncovered and the Fireflash fleet shall start operating again. Before they can hear anymore, however, the power suddenly cuts off. When Grandma informs them that a fuse in the oven blew, Scott and Virgil teasingly say that after the stint with the Fireflash, Gordon should have no trouble fixing the problem. Realising that his comments about "just like fixing a fuse" have backfired, Gordon heads off into the kitchen, whilst his father and brothers laugh in amusement.