At London airport, Fireflash 3 is given clearance to take off. The plane takes off without a hitch, but minutes later, the control tower receives a mayday signal from it. The signal is not very clear, but the control tower staff hear the pilot say that they are losing height rapidly. The signal then cuts out completely, and Lt Burroughs sends out the air sea rescue jets. The jets go and look for Fireflash at the plane's last known co-ordinates.
As the jets take off, Controller Norman also has the Navy divert some of their ships to check the seas. The search is on, but neither the jets or the boats find anything, it seems that Fireflash 3 has just disappeared. The rescue craft are told to return to base.
Later on at London Airport, the International Air Minister calls a meeting with Commander Norman and some of the other staff, saying that it is not good enough -not only have they lost the 5 million pounds Fireflash 3 cost to make, but 600 lives have also been lost. Effective immediately, he tells Norman that all Fireflash jets are to be grounded, and he wants them tested thoroughly -they must have a fault somewhere, and it must be eliminated.
News soon spreads of the Fireflash jets been grounded, and on Tracy Island, some of the family watch a news report about it. The reporter mentions that earlier this year, another Fireflash had a bomb fixed to it, and it was only thanks to the efforts of International Rescue that the plane was saved. However, this time there were no survivors. John wonders if it was sabotage again, but Tin-Tin thinks they take so much precaution now it couldn't have been. Jeff wonders how a plane like that would just vanish.
He contacts Alan in Thunderbird 5 and asks him to monitor all transmissions about the Fireflash tests. Alan says he will and then mentions something about Fireflash 3 -according to their automatic fixer, the Fireflash crew gave out the wrong position before they disappeared, and were 50 miles out. Jeff says that is strange and tells him to keep listening out for any more info. He then contacts Scott, Virgil and Gordon and tells them to be on standby as further tests are being carried out on Fireflash, and it could mean trouble.
Back at the airport, extensive tests are been carried out on one of the Fireflash jets. Patterson, one of the engineers, has done everything possible and all the tests done show that there seems to be nothing wrong with the plane. Norman later calls a meeting, as the next step is to send one of the Fireflash jets on a test flight -he tells the two pilots that they are to go on the same route as Fireflash 3, and to keep in constant radio contact.
The test Fireflash later takes off from London airport without any trouble, and heads on a route that should take it to San Francisco. However, as the pilot reports their position, Alan is monitoring it and realises the position the pilot just gave is actually 20 miles out of their actual location.
The co-pilot of the jet sees that the elevator power unit has suddenly stopped working. The pilot attempts to contact the control tower, but his message cannot clearly be heard. He manages to give the position of the plane, as it begins to lose height. Norman realises that this Fireflash is having the same trouble in the same position as Fireflash 3.
As the plane continues to descend, someone jumps out of it. Meanwhile, Alan lets Jeff know of what is happening, and how the test Fireflash is not in the place where the pilots say it is. Scott, Virgil and Gordon are is the shooting gallery when their father tells them to be ready.
The test Fireflash crashes into the sea. The pilots try and get out, but the emergency exit door has jammed. The plane starts to sink.
Meanwhile the guy who jumped out earlier has used in inflatable dingy and uses a flare so a large aircraft comes to pick him up. Back on Tracy Island, Jeff tells Scott to go out in Thunderbird 1 and land near the coast of the crash site, where he can set up a base. He then tells Virgil to get Brains and Gordon to go with him in Thunderbird 2, and to take Thunderbird 4 with them. A few minutes later, Thunderbirds are go.
Thunderbird 1 lands in Ireland, surprising a farmer. Meanwhile Thunderbird 2 is a short distance behind, and Brains asks Virgil to have London airport to send circuit diagrams of the Fireflash via radio photograph, as he may need them. Back at the farm, Scott has set his mobile control up in one of the farmer's barns.
Scott has got a scanner system placed outside, which begins to search for the crashed Fireflash. Brains has received the circuit diagrams and has a look at where something may have gone wrong, and thinks that if the gyro shaft sheared, it could have damaged the main hydraulic power supply to the flaps, causing the plane to dive and crash. Gordon asks if the plane could have crashed into the sea, but Virgil doesn't think so as they haven't received a S.O.S. from their life boat. However Brains thinks that they may not have been able to get out of the cockpit, as the emergency door would have jammed if the hydraulic power was out. Meanwhile, the test Fireflash has sunk to the bottom of the sea.
The pilots try to contact London airport but can't get through. Thunderbird 2 reaches the sea and Virgil drops the pod, letting Gordon in Thunderbird 4 launch. Scott's scanner hasn't found anything, but he tells Gordon some co-ordinates of where the plane last reported to be.
Gordon starts looking around but only finds the Fireflash when the crew attract his attention by flashing a light in the cockpit repeatedly. He tells Brains that the plane seems to be in one piece, although he can't seem to see any signs of life. Brains tells him to use Thunderbird 4's laser beam to cut off the plane's engines, as once that is done, it will float to the surface.
Before he does that, Gordon gets out of Thunderbird 4 and swims over to the plane, where he sees that the pilots are alive. He uses a machine that he can type messages on to tell them what he is about to do, and then gets back into Thunderbird 4 and starts using the laser beam on the left engine.
He eventually cuts through it, and it falls off the plane. He then heads over to the other engine and cuts it off in the same way.
With the engines off, the plane starts to float and reaches the surface. Just in time, as the crew were running out of oxygen and, worse yet, some of the instruments have begun to catch fire! Gordon gets out of Thunderbird 4 and uses a small portable laser to start cutting through the cockpit's glass.
The fire is getting worse, as Thunderbird 2 hovers over Fireflash and lowers down a small pod for the crew to get out on. Gordon finishes cutting through the glass and tells the pilots to get into the rescue capsule.
He then dives back into the water and gets back into Thunderbird 4. The pilots get inside the capsule and Thunderbird 2 moves away, just as Fireflash explodes.
Some time later, the family watch a news report about how International Rescue saved the day and sent a report to London airport, highlighting what may have been the fault in the plane. Scott then returns, as he had to milk the cows before he took off. At least he got some free dairy products out of it. Alan then contacts Tracy Island, saying he has been monitoring the messages from London airport. A top level meeting about the Fireflash is going on right now.
At the meeting, everyone is arguing over what the fault could be and they have got it narrowed down to three things, all to do with the hydraulics system. What actually causes the fault is a mystery, and all they can do is check each of the three theories they have. Meanwhile Jeff decides that it is time International Rescue were involved in the next Fireflash test, and he has a letter sent to London airport. Norman checks it out.
It states that International Rescue want to test the Fireflash out themselves, and he decides that they can. He has it arranged so Captain Hanson will be available on the next test run, and then gets ready to have the airport shut down, as he wants this test to be done in top secret. A short time later, Alan contacts Tracy Island and says the airport is getting prepared for Thunderbird 2's arrival. Virgil has already crossed into the British coast.
Norman has Captain Hanson move the new test Fireflash out onto a runway, before he has the whole airport cleared out. Thunderbird 2 then arrives and lands next to Fireflash.
Jeff tells Alan that he wants him to maintain constant contact between himself, Thunderbird 2 and Fireflash. Scott has gotten onboard Fireflash, and after checking that their radios are working, he and Hanson take off.
The control tower then gives clearance for Thunderbird 2 to launch, and it takes off and follows Fireflash. Fireflash goes from being over land to over sea in no time at all, and Scott wants a position fix. He tells Alan what Fireflash's instruments are stating, only to find out that the reading is wrong -Alan reports that Fireflash is 20 miles off course already.
Hanson reports this to London airport, as Fireflash begins to develop the same problems the previous test had. His message is received in the control tower, but the line is bad again and the radio soon cuts out completely. Norman says it is the exact same pattern as before.
However Scott has a special radio onboard and uses it to contact Alan and Virgil. He tells Alan to relay any messages from him to the control tower, and mentions that they have lost their elevator power unit and the radio system on the plane has stopped working. Fireflash has gone into a dive, and they can't get the nose of the plan to move up. The control tower staff suggest the pilots bail out, but Scott wants to know why the plane is going to crash. Virgil suggests they go ahead with a little plan they have thought up, but they have to hurry -they only have 15 minutes until Fireflash hits the sea. Gordon gets ready...
...as Thunderbird 2 speeds up and gets underneath Fireflash. Scott opens up part of the starboard wing and a line is fired from Thunderbird 2, entering the opened hatch. Gordon moves up this line on a special machine, and enters the plane. He starts to take a look around, but with the amount of time passed as he got onboard, he only has 4 minutes to find the problem and fix it.
He finds the elevator power unit, and finds that the main power wire has been cut! He then has to take cover as someone fires a shot at him. There is another man on the plane, who says he's ready for International Rescue. Gordon draws his gun but is reluctant to fire due to all of the equipment in here, he knows that if a shot missed it could end up destroying something valuable. However, the other guy doesn't care about that, and says that in a couple of minutes, this plane will crash into the sea, like all of the others.
A short gun battle ensures, but the saboteur keeps looking at the open hatch. Gordon advises him not to jump, as his parachute will never open in time, but he makes a run for it. Gordon shoots him and he tumbles out of the plane. With only 10 seconds left, there is only one thing Gordon can do to restore power to the EPU...
...and that is to hold the wiring together manually. This restores power, and Scott and Hanson manage to stop Fireflash from crashing into the sea at the last moment.
Later on at Tracy Island, a news report states that the Fireflash planes are no longer grounded, and will resume service. He also says that thanks to the efforts of International Rescue, the police have completed their investigation and have unmasked an International gang, who were bent on aircraft espionage. The TV suddenly cuts out, as Grandma Tracy enters the room and apologises -she was cooking and the fuse in the oven has just blown out, hence the power cut. Virgil suggests Gordon goes and fixes it, and Scott reminds him of what he said after he restored the EPU on Fireflash -it was just like fixing a fuse. Gordon says here he goes again, getting some forced laughter out of everyone else.
NOTES