Distress call

A distress call was any signal that requested assistance. It was typically sent by an individual or group that encountered a problem they could not handle on their own. The purpose of the signal was to summon those who could help.

Notable examples
The Twelfth Doctor loved distress calls, and considered them "[his] theme tune". As he had learned, "You only see the true face of the universe when it's asking for your help." (TV: Oxygen) He later called taking the TARDIS out and looking for distress calls "our usual Saturday" while talking with Bill Potts and Nardole. (TV: World Enough and Time)

According to the Fourth Doctor, the first rule after surviving a crash landing was to set up a distress beacon. Indeed, it was what a survivor Rutan Scout intended to do after crashing on Fang Rock. (TV: Horror of Fang Rock)

Most Daleks could emit an automatic distress call if their casings were tampered with. (TV: Planet of the Daleks)

In the year 37,166 the Fourth Doctor and Sarah Jane Smith responded to a distress call from Zeta Minor. A space crew landed shortly after their arrival on the planet. (TV: Planet of Evil)

Lord Cardinal Hemal sent a distress call to the Fifth Doctor to investigate a Time Lord murder. It was soon discovered that the murder had been caused by a vampire. (COMIC: Blood Invocation)

When Turlough and the Fifth Doctor went to Sarn, Turlough sent a distress call to Trion requesting assistance for the people, who were threatened by a volcanic eruption during the Time of Fire. (TV: Planet of Fire)

When they learned of the imminent arrival of a blue star to their solar system, the Antarians sent out a distress call, but were shortly afterwards wiped out by the Valerons, who also destroyed their world, with Dynil the only survivor. (PROSE: A Universe Called Fred)

The Tenth Doctor and Martha Jones received a distress call from New Earth when the Cybermen and Judoon joined forces to catalogue all the humans on the planet. (COMIC: In-Flight Entertainment)

In the 42nd century, the Tenth Doctor and Martha responded to an automated distress signal from the SS Pentallian which was on a collision course with Torajii. After the Pentallian reached safety, the crew sent out an official mayday and Riley Vashtee reassured the Doctor and Martha that the authorities would pick them up soon enough. (TV: 42)

Alonso Frame sent a distress call for the Titanic to be salvaged after the defeat of Max Capricorn. (TV: Voyage of the Damn)

After the Crusader 50 inexplicably stopped on the planet Midnight, the driver Joe and mechanic Claude sent out a distress call and reassured the Tenth Doctor that a rescue vehicle would soon arrive. The bus's cab was destroyed by the Midnight entity which then besieged the vehicle. After the Hostess sacrificed herself to save the Doctor and everyone else onboard, the distress call resulted in the survivors being rescued a short time later. (TV: Midnight)

K9 was capable of sending an emergency distress call, as K9 Mark 2 attempted to do when he was attacked by the Anubian Nehetka. (TV: Curse of Anubis)

When the spaceship they were honeymooning on ended up on a collision course towards a planet, Amy Pond and Rory Williams sent out a distress call from the honeymoon suite in hopes of being rescued by the Eleventh Doctor, much to the shock of the ship's captain. The Doctor quickly responded to the distress call, but was unable to help the ship land due to the nature of the planet's clouds and instead had to enlist the help of Kazran Sardick to help the ship land safely. (TV: A Christmas Carol)

Hundreds of Time Lords, who were stranded in the bubble universe by House, used hypercubes to send distress calls. The Corsair's hypercube arrived in the main universe and found the Doctor's TARDIS. After the Eleventh Doctor arrived in the bubble universe, he heard the distress calls on Nephew's translation sphere and assumed this meant there were living Time Lords. Unfortunately, all the Doctor found was a cabinet filled with hypercubes, as House had murdered every Time Lord whom it had encountered. (TV: Doctor's Wife)

During the Battle of Demons Run, the Doctor had a squad of Dalek-upgraded Spitfires destroy the communications array of Demon's Run so Colonel Manton would not be able send a distress call to his fleet. (TV: A Good Man Goes to War)

The Eleventh Doctor also picked up a distress call inside his TARDIS from Terrin and Alyst Blakely, who were being attacked by Daleks. (PROSE: The Dalek Generation)

Renegade Time Lord Drax made the Shadow a device which would transmit an Intergalactic Computer Distress Signal, which he then used to capture K9 Mark II. The Fourth Doctor picked it up in the TARDIS, and used a portable receiver to try to find the source, but was captured instead. Drax claimed to the Doctor that he had built it to try to escape from the Shadow, but that it had gone missing. (TV: The Armageddon Factor)

A sentient cell culture (the Culture), endangered by a virus infection, was able to send a telepathic distress call to the Seventh Doctor. (COMIC: Culture Shock!)

After awakening on the Firebird in 1983, Grand Marshall Skaldak activated a distress signal from his armor in an effort to get the rest of the Ice Warriors to rescue him. After they failed to show up, Skaldak took it as a sign that his species was extinct. However, an an Ice Warrior starship eventually arrived in response to the distress call, raised the Firebird to the surface and teleported Skaldak onboard. (TV: Cold War)

After hearing a noise coming from King Hydroflax's head, the Twelfth Doctor suggested that it could be a distress call. However, River Song realized that it was actually a homing beacon that Hydroflax's cyborg body was following to them. (TV: The Husbands of River Song)

In an effort to test 's redemption, the Twelfth Doctor decided to "take the TARDIS for a spin and graze for distress calls" before picking a good one. The Doctor referred to this as "our usual Saturday." The Doctor ultimately had Missy respond to a distress call from a Mondasian colony ship with the help of his companions Bill Potts and Nardole. The distress call turned out to be because the ship had gotten stuck too close to a black hole. (TV: World Enough and Time)

The Thirteenth Doctor and Team TARDIS discover nine different distress calls coming from the planet Ranskoor Av Kolos. Investigating, they discovered that they came from ships brought down due to the efforts of the rogue Stenza Tim Shaw. (TV: The Battle of Ranskoor Av Kolos)