A Search is Underway for a Downed U.S. Crew Member in Iran. Here’s What the Mission Could Entail

A search and rescue mission is underway after a U.S. fighter jet crashed inside Iran on Friday. 

Two crew members were aboard the F-15 jet when it crashed. The pilot was rescued by U.S. forces, while the search for the second crew member is ongoing, Axios and CBS News reported Friday afternoon, citing unnamed U.S. officials.

TIME spoke with Brigadier General Houston Cantwell and Major General Thomas Kunkel about what the rescue effort might entail, and how the military goes about locating and securing lost crew members. 

“We spend our entire careers training for this scenario and so there is no better trained and prepared force to go and execute this mission,” says Kunkel, who was a rescue helicopter pilot for the U.S. military. “We go to extreme lengths to make sure we rescue and take care of our aviators that go into harm's way.”

Here’s what to know about how the military carries out search and recovery operations. 

The rescue process

“It is a very complex effort,” Cantwell tells TIME.

The military is often alerted that an aircraft has gone down when a crew member ejects, which sends off an alert, he explains. The first and foremost priority is then to locate the crew members. 

“The most important piece of information is what is the location of the air crew. And that piece of information is so hard to get,” he says, noting that enemy forces are likely to attempt to “spoof” or put out false information regarding where a lost crew member might have landed. “It seems so basic, but it is so hard.”

Air Force fighters are trained for scenarios like this through a rigorous training program known as SERE (Survival, Evasion, Resistance, and Escape). For stranded crew members, “the situation can be so dynamic that there's no one thing you can do,” Cantwell says. 

“It might have been years [since] they've had the training, but I guarantee you that it kicks in right away,” Kunkel added, referring to SERE. He noted that “there’s always refresher training that occurs” prior to combat missions. 

Crew members are usually equipped with survival kits that stay with them when they eject from an aircraft and might contain some type of radio device to communicate with U.S. personnel. 

Once a crew member is located, a “rescue package” is put together involving several pieces of equipment and personnel that rely on a series of environmental and situational factors to successfully execute a rescue.

The personnel and equipment 

Kunkel estimates based on prior missions he’s been on that a roughly 10- to 20-member crew would be deployed in the search and rescue operation currently underway for the downed crew member in Iran.

The helicopter used for a rescue of this sort, according to Kunkel, is the HH-60W, which he says was built for these kinds of missions. Because these helicopters often have to travel such long distances to carry out rescues, refueling aircraft—specifically the HC-130J—will be deployed to ensure the HH-60Ws have enough gas. 

Cantwell adds that an electronic jamming aircraft may also be deployed to provide cover for the operation. And an A-10, a heavily armored aircraft designed to attack ground forces, will provide another veil of cover to defend against enemy forces. 

“If there's any enemy forces that need to be suppressed during the actual extraction, then the A-10 will provide that suppressing fire to allow the rescue aircraft to get in there,” he tells TIME.

Despite the complexities and dangers of the rescue mission underway in Iran, Kunkel stresses that there’s no force better prepared to take on the challenge. 

“The Air Force is the only service that specifically organizes, trains, and equips for this mission,” he says. “We want them to know that there will be every effort made to come rescue them.”

Key considerations and concerns 

A number of different factors can impact a rescue effort.

“Whether it's day- or nighttime has a significant factor,” says Kunkel. He notes that daytime rescues can turn into a “race” with enemy forces because operations can easily expose the location of a crew member.

“If the enemy knows that we're going to send rescue forces, they're also going to be looking to try to probably shoot down those rescue forces,” he says. “Being able to operate under the cover of darkness is a big risk mitigator, especially from your … less advanced threats.”

Another key consideration is whether or not the stranded crew member is mobile––”a really important, key piece to this,” Cantwell says, as a crew member being immobile restricts the range of locations from which a rescue can be carried out.

Rescue crews will also weigh environmental factors, such as whether or not a crew member is surrounded by foliage or thick brush, which can eliminate the possibility of a rescue helicopter landing. In that situation, the crew may use a tool called a force penetrator, which can hoist someone onto a helicopter without it having to land. 

Cantwell’s biggest concern for this particular rescue mission is the possibility of capture. 

“I am certain that the Iranians would want nothing more than to get their hands on one of our aviators,” he says. “It's our aviators that have been inflicting this destruction on their country for the last three weeks.”

If the U.S. crew member still being searched for evades capture, Cantwell is most concerned about their survival in harsh desert conditions. 

“The thing I'd be most worried about is simply water. If you found yourself in the desert, there's not much places to conceal yourself,” he says.