a jumpseat is called a "forward observer's seat" in the Federal Aviation Regulations. It exists so that check pilots giving checkrides and other persons with a need to observe flight operations can have a seat to occupy on the flight deck. Don't know where the word "jumpseat" originated but it refers to any fold-down seat and is as old has horse-drawn carriages.
Most common use for them just now is for online commuters, followed by Company or FAA enroute checkrides. Some aircraft have more than one. Long-haul two-pilot aircraft like A-330 or B-767 that frequently use three pilots for international pilots will have a seat for the IRO plus a jumpseat. Older aircraft that had a flight engineer (B-727 e.g.
) might have one jumpseat for a check engineer and one for a check pilot.
Under the US FARs, there are two regulatory cases. One is for people whose seat onboard the aircraft IS
the jumpseat, and another for people who have a seat assigned in the passenger cabin but who may have need to occupy a flightdeck seat for a portion of the flight. There are different criteria for each case. In one case it is open to any person
who has the permission of the [airline] but that permission has to be granted in compliance with their FAA-approved operations manual.
The jumpseat regulations are pre-9/11 and have been superseded by a tougher law.
I am a long distance commuter and while I "ride jumpseat" offline, I have to be seated in the cabin. That means there has to be a seat available for me in the cabin.
One last thing about jumpseats. The FAA does not care
how many jumpseaters a given flight has. You can have one jumpseat in the cockpit and fifty jumpseaters onboard the plane. It is an economic consideration and the FAA just does not care how you solve it. What they do insist on is that each person on board the aircraft, no matter whether ticketed or not, has a seat, with a seatbelt, and if on the flight deck, has a quick-donning oxygen mask. Every airline out there that only grants one jumpseater for each seat on the flight deck needs to be targeted by their own and other pilots to fix their stupid policy. It just unecessarily leaves people behind.
Happiness is not seeing another trite Ste. Maarten photo all week long.