When looking at possible jets to purchase in the long and ultra-long-range segment, it is important to look carefully at how many seats are certified for take-off and landing. This is different than how many seats have seat belts. Just because a seat has a seat belt does not mean that it is certified to carry a passenger during times when passengers are legally required to be seated, such as taxi, take-off and landing.
A certified seat means it has gone through the legal requirements for safety during a crash or incident.
This issue of possible non-certified seats is most often seen in divans. It is not unheard of for divan seats to not be certified. As a result, the interior may appear to have 15 or 16 seats but is only certified for 10. This can make a big difference to the use of the aircraft.
An aircraft with less certified seats is not a bad aircraft or one to completely disregard, but it will have an implication on your use as well as your resale value. Most buyers are looking for max passenger capacity and having a divan that cannot be used during take-off and landing is not ideal.
Having uncertified seats will decrease the desirability of the aircraft and therefore decrease its value. When a buyer is comparing an aircraft that is similar except one has 10 certified seats and the other 16, they will most often choose the one with more capacity. To counter this, the asking price must be attractive. You can of course undertake the work to install certified seats, but it comes at a steep cost.
This can be a tricky component and one to discuss with your broker as you search for a long or ultra-long-range aircraft.