- "They're crazy! It's probably a million to one chance we'd get hit."
Two men are endangered when an aircraft sabotaged by the Hood crashes into their Telerelay Station. The Control Room at the top is swaying in the wind and will soon collapse. They cannot be rescued directly, but a capsule fired from Thunderbird 2 contains escape harnesses for the men, and when the structure finally falls the two are saved.
- Main article: Edge Of Impact/Storyline
- Main article: Edge Of Impact/Transcript
- Jeff Tracy - Peter Dyneley
- Scott Tracy - Shane Rimmer
- Virgil Tracy - David Holliday
- Alan Tracy - Matt Zimmerman
- Brains - David Graham
- Tin-Tin Kyrano - Christine Finn
- Gordon Tracy - David Graham
- The Hood - Ray Barrett
- Commander Norman - Peter Dyneley
- Colonel Tim Casey - David Graham
- General Bron - David Graham
- Goddard - Matt Zimmerman
- Jim - David Graham
- Stan - Ray Barrett
- Race - David Graham
- Control Tower Lieutenant - Ray Barrett
- Foreign Fighter Jet Captain - Matt Zimmerman
- 1st Policeman - David Graham
- 2nd Policeman - Ray Barrett
- Police Radio (not seen on screen, voice only) - Christine Finn
International Rescue Equipment UsedEdit
- Thunderbird 1
- Thunderbird 2 (Pod 3)
- Booster Mortar
- Remote-Control Hover Camera
- Low-altitude Escape Harness
Non-International Rescue Equipment UsedEdit
- British Telecom Tower
- Control Tower - London International Airport
- Hill-Top Bunker (W27)
- The Hood's Temple
- Installation "Y"
- London Airport Military Facility
- London International Airport
- The TX-204 aircraft originally seen in Trapped in the Sky appears briefly in an establishing shot of the airfield. A WASP Spearhead bomber from Stingray is also visible in the background.
- Tim Casey also appears as a bank executive in the opening shots of Vault Of Death.
- The Hood's North Pole Laundry Truck is revamped from Ned Cook's broadcasting truck seen in Terror In New York City.
- Braman, Brains' robot from Sun Probe, can be seen in Brains' laboratory.
- This is one of the few episodes in Australia where a subtitle is added; 'Part 1' is shown under the title in the Australian 30 minutes cliffhanger version.
- The Hood gives his codename as '671' when he contacts General Bron.
- Jeff's comments about their unexpected visitors being "more of Tin-Tin's admirers..." refers to the events of End Of The Road, which confused many people as this episode was broadcast after Edge Of Impact.
- In a startling prediction of the future, the relay tower is shown to be owned by British Telecommunications Ltd; the real life British Telecommunications didn't come into existence until 1980, 16 years after this episode was produced.
- The shot of the Target Ship exploding is stock footage lifted from the start of the Stingray episode Star of the East.
- Tim Casey is a colonel, but Scott refers to him as a "General" in one scene. ("I guess I just thought that with you and the 'General' being buddies in the early days...")
- In the close-up puppet shots of Virgil at the danger zone, he is wearing a white coat, but in the model long-shots, he isn't wearing it.
For a contemporary (or at least in the 1990's) audience, Thunderbirds underwent a repackage, redub, and rebroadcast as part of FOX Kids' Saturday morning line-up. The sixth story to be produced in this fashion was Edge Of Impact, first (and last) aired on August 6th 1994 at 8:30am.
- French: Essais en vol
- German: Red Arrow ausser Kontrolle
- Italian: Impatto imminente
- Spanish: Impacto Inminente; Al borde del impacto (DVD)
- Dutch: Sabotage (TV 1967); Op het randje na dood (TV 1991); Een vlijmscherpe inslag (DVD)
- Japanese: 超音ジェット機レッドアロー
- Main article: Edge Of Impact/Gallery