how do pilots sleep on long flights? do their chairs recline all the way back?

The 747 has a Pilot Rest area on the upper deck.

The C-5A has 2 small rooms with 3 bunks for crews to rest in.

The C-141 has a elevated deck in the Cargo hold with 2 bunks.

The C-130 has 2 bunks on the Flight Deck.

In the case of LONG flight spare crew are brought and bedded down in these areas. At a certain point they take over from the 1st crew.

The seats recline but not all the way back. Some aircraft have a crew bunk for additional crew members. There is always someone in all the seats at all times. Occasionally one pilot might take a short catnap in order to be refreshed for the approach. For the most part we are awake the whole time. Turn the cockpit lights up bright and keep busy.

I did mostly transatlantic flights and 8 hrs went by fairly quickly.

There may be a crew rest bunk, or area where a few beds and chairs are totally devoted to the pilots, only used when there are relief pilots on duty... obviously, there is no sleeping allowed between the two active pilots... Other flights will simply put a relief pilot in a first class seat and he will rotate in with the pilots in the cockpit...

Well, I can only speak to 2 different aircraft from personal experience:

US Navy P-3C Orion - A converted airliner used for Antisubmarine & Maritime Patrol. We used to do 15-20 hour patrols, and carried 2 flight deck crews (pilot, co-pilot, flight engineer)... there were two bunks in the AFT of the aircraft for the pilots. Us Sensor operators would just unroll sleeping bags on the cabin floor for a nap during the flight out to our patrol station. The length of time from PRE-FLIGHT to Post-flight briefings was OFTEN 30+ hours.

US Navy SH-60B Seahawk - The pilots might switch off a "nap" during LATE night patrols... just boring holes in the sky from 2000 to 0500. Seats didn't recline at ALL... you just cinch up your harness and nod off. Crew of three, and ONLY one was permitted to nap at a time... the other two would keep talking.

No, they trade shifts with other pilots, or the co-pilots and there are little bunk rooms for the flight attendants and pilots to sleep in!

In a documentary on the Boeing 747, they showed a little room in which there were 2 small beds for extra pilots to lie down on a very long trip. Two crews were on the trip, one to fly half way, and the other to relieve them.

The crew is provided sleeping quarters on the aircraft designed for long haul flights. The area is kind of like a loft and is called the crew rest area. Dependent on the type of aircraft it can have up to 6 bunks.

If you're referring to commercial flights, in heavy transports, they don't unless there's a backup pilot to give them relief. And the airline isn't going to put additional crew on an airline flight less than eight hours long.

When relieved by alternate crew, they take the same seats in first class that the alternate crew came out of to sleep in.

The B-52 actually features small berths for pilots on long missions, (the airplane could stay in the air for as long as 24 hours on some of the patrols,) so one crew replaced the next, with the retiring crew heading to very small berths aft of the flight deck.

As to private aircraft, I know of a pilot that does sleep in flight, (he carries an alarm clock and airline pillow in his flight bag,) and a pilot who keeps managing to hide narcolepsy from his physician every year when he goes for a medical.

The front seats of some aircraft will fully recline, on larger aircraft, they're typically blocked by the bulkhead between the flightdeck and the cabin.

Let me say here that a pilot in command of an aircraft should never allow their attention to stray from the task of flying the airplane. Think of trying to take a nap on a long stretch of nice straight highway; if you're that tired, you don't need to be driving, or flying.

JT

Surprisingly it isn't uncommon for the entire flight crew to fall asleep on international cargo flights. 12 hours is a long time to baby sit the auto pilot and hand plot the route.

pilots take turns on 30 minute power naps like on trans-atlantic/pacific flights,