After a pilot tried to bring a plane down, what exactly are the rules and risks around jump seats on flights?

A 44-year-old pilot, Captain Joseph David Emerson, is in custody in Portland, Oregon facing 83 counts each of attempted murder and reckless endangerment as well as a charge of endangering an aircraft.

On 22 October 2023 Captain Emerson was travelling off-duty in the “jump seat” on the flight deck of a Horizon Air jet flying from Everett, north of Seattle, to San Francisco.

He is accused of trying to disable both engines by deploying the engine fire-suppression system on the plane. He later told police afterward he had taken “magic mushrooms” two days earlier and had not slept in 40 hours,

The incident highlights the use of “jump seats” on aircraft – and the wider issue of pilots deliberately putting passengers and crew at risk.

What happened to Horizon Air flight 2059?

Eighty passengers and four crew members were on board the Embraer 175 aircraft. As the plane was approaching Salem at a cruising altitude of 31,000 feet, he tried to shut down the engines.

The crew managed to subdue Captain Emerson and move him out of the flight deck, which was then locked in accordance with Federal Aviation Administration (FAA) rules. The aircraft diverted to Portland, with the pilots telling air-traffic controllers: “We want law enforcement as soon as we get on the ground and parked.” Mr Emerson was arrested, while passengers continued to San Francisco on a different plane. The original aircraft is now back in service.

Horizon Air is owned by Alaska Airlines, which said in a statement: “Captain Emerson unsuccessfully attempted to disrupt the operation of the engines. The Horizon captain and first officer quickly responded, and the crew secured the aircraft without incident.

“Engine power was not lost despite the off-duty pilot’s attempt to shut down the engines by engaging the engine fire handle, also known as the fire suppression system.

“The fire suppression system consists of a T-handle for each engine. If the T-handle is fully deployed, a valve in the wing closes to shut off fuel to the engine. In this case, the quick reaction of our crew to reset the T-handles ensured engine power was not lost.

“Our crew responded without hesitation to a difficult and highly unusual situation, and we are incredibly proud and grateful for their skilful actions.

“Following appropriate FAA procedures and guidance from Air Traffic Control, the flight was safely diverted to Portland.

“Throughout his career, Emerson completed his mandated FAA medical certifications in accordance with regulatory requirements, and at no point were his certifications denied, suspended or revoked.”

Why are jump seats fitted, and who can use them?

One or two jump seats may be fitted to flight decks to provide space for for the purposes of training (including for air-traffic controllers as well as pilots and inspectors). When no passenger seats are available, they may be used to carry other people. The rules are set by national aviation authorities and vary from one country to another. They may also differ for domestic and international flights.

In some jurisdictions, only a very limited categories are allowed to occupy a flight deck jump seat – typically crew involved in training, screened airline personnel and government officials. In others the options may be wider, including pilots who work for other airlines.

In addition, jump seats are installed for cabin crew around the aircraft. They are typically located at bulkheads and are normally folded away except during take-off and landing.

Why are jump seats used?

Most of the time jump seats are not being used for “official” purposes – ie only the two pilots are on the flight deck, and the number of available jump seats in the cabin exceeds the number of cabin crew.

When the plane is full, the view is taken that jump seats in the passenger cabin may as well be occupied by “non-revenue” travellers. These include:

• staff flying as part of their duties (eg flight crew “positioning” to another airport)
• off-duty staff
• family or friends of staff who are travelling on free or heavily discounted tickets

Has someone in a jump seat jeopardised a journey in the past?

In 1994 a FedEx flight engineer, Auburn Calloway, was travelling on the flight deck of a cargo DC10 aircraft and, in a pre-meditated attack, attempted to kill the captain, first officer and engineer in order to crash the plane.

Calloway had earlier been accused of falsifying flight hours and was facing possible dismissal. He used hammers and a spear gun – which he had smuggled on board in a guitar case – to attack the three flight crew. But they overcame Calloway and safely landed the aircraft despite being badly injured.

There are rather more cases in which a third, off-duty pilot has assisted the captain and first officer.

In 1989 Captain Dennis Fitch was travelling as a passenger aboard another DC10 operating United flight 232 from Denver to Chicago. A catastrophic failure of the engine in the tail led to the loss of most controls. But Captain Fitch had experimented on a flight simulator with controlling an aircraft using only the engine throttles. The plane made a crash landing and 184 of the 296 people on board survived.

On 28 October 2018, a third pilot on the flight deck of a Boeing 737 Max belonging to Lion Air and flying from Bali to Jakarta identified that the “Maneuvering Characteristics Augmentation System” (MCAS) was malfunctioning and told the captain and first officer how to fix the problem.

The aircraft landed safely. But the next day the same fault occurred on Lion Air flight 610 from Jakarta to Pangkal Pinang. The plane crashed with the loss of 189 lives. Soon afterwards the Boeing 737 Max was grounded worldwide while the MCAS was overhauled.

How common is pilot suicide?

Cases of flight crew deliberately crashing their aircraft in a bid to kill themselves and everyone on board are rare. The vast majority of “aircraft-assisted suicides” involve small private planes.

The most recent significant proven example of a pilot murdering everyone on board was Germanwings flight 9525 from Barcelona to Dusseldorf on 24 March 2015. The first officer, Andreas Lubitz, used his expertise to lock the captain out of the flight deck of the Airbus A320, which he subsequently flew into a mountainside in the French Alps. He knew that the procedures implemented since 11 September 2001 enabled someone on the flight deck to take total control.

Until the 9/11 attacks, most passenger aircraft had a fairly flimsy door between the cockpit and the cabin, because an attack on the pilots and a takeover of the aircraft was considered implausible. The 9/11 hijackers, armed with blades that they had taken through security, were able to access the flight deck and kill the pilots to take control. After the terrorist attacks, airlines began to install reinforced doors that are intruder-proof and bullet-proof.

Only one alleged pilot suicide has killed more people: EgyptAir flight 990, flying from New York to Cairo on 31 October 1999. The Boeing 767 crashed in the North Atlantic, killing all 217 passengers and crew on board. The US safety authorities concluded the crash happened “as a result of the relief first officer’s flight control inputs” but did not ascribe a motive.

The loss of MH370, the Malaysia Airlines flight that disappeared on 8 March 2014, remains a mystery. One theory is that the aircraft’s commander, Captain Zaharie Shah, intentionally hijacked his own aircraft in order to take his own life and kill all 239 passengers and crew. The Boeing 777 jet had taken off from Kuala Lumpur on a routine flight to Beijing. Air-traffic controllers lost contact with the aircraft, which flew south across the Indian Ocean before crashing in an area west of Australia.

The investigators’ last word on the greatest mystery in aviation history appears on page 443 of the MH370 Safety Investigation Report: “The Team is unable to determine the real cause for the disappearance of MH370.”

One person close to the saga believes the plane will be found in the southern Indian Ocean once undersea drone technology makes it feasible to deploy 100 or more unmanned devices to plumb the depths for signs of former life.

Only if and when divers assess the wreckage will a narrative start to emerge. Even then, the grieving relatives may never know the full story of how and why their loved ones died.