Aircraft Seats: How Many Should My Plane Have?

The number of seats that an airplane has is a function of the design of the aircraft. In short if the plane is too small or does not have enough payload to carry more than one average size individual then the plane should be built and marketed as a single place aircraft. The same is true for two, three and four place considerations. However, the aircraft market is wrought with two, three and four place planes that have barely enough payload to be considered such. Despite this they have received that designation as a result of the number of seats installed in the plane. Such attempts are merely marketing schemes and most pilots are familiar with the claims that some prominent aircraft companies of the 1960's and 1970's allowed the marketing departments to author the aircraft specifications. While these claims are likely rooted in folklore rather than truth, the fact remains that planes are often produced with more seats than they have payload to support. So the question is why is this practice widespread and how should a pilot consider such planes when making a purchasing decision.

Aircraft payloads are determined with and without fuel. The full-fuel payload is the payload of the aircraft not including the fuel, oil etc. In other words the fuel and other essentials for flight are considered to be part of the aircraft rather than part of the payload. This is the easiest and safest payload to consider when purchasing or operating and aircraft. By using the full-fuel payload the pilot is never limited on the amount of fuel which he/she can carry but instead is limited on the amount of people and baggage which they can carry. On heavy haulers like the Cessna 210, Piper Cherokee Six and the Piper Dakota, the full-fuel payload leaves ample room for the pilot to fill all of the seats on the airplane. However what about the Piper Cherokee 140 and the 150 hp Cessna Cardinal. These are two extreme examples of aircraft that were built with too many seats. In fact these two aircraft in particular can bareley fill all four seats with descent size adults when they are carrying no fuel at all. While these are extreme cases, even one of the most popular aircraft of all time the Cessna Skyhawk has more seats than it can fill with full fuel. The full-fuel payload of a typical Cessna Skyhawk is around 450 lbs. If you consider an average individual to weigh 150 lbs which is probably an underestimation then the Skyhawk is barely a three place plane despite the fact that it comes equiped with four seats. In order to leave enough fuel on the ground to get another individual into the plane the pilot must effectively cut the range of the aircraft in half.

Aircraft companies take the stance on this issue that most people will want to stop long before they exhaust their fuel supply even with half a tank of gas. Therefore for them it is acceptable practice to produce an aircraft with insufficient payload to carry full fuel and full seats. However the truth is that this practice likely puts many pilots in the tempting position of overloading their planes. The scenario is that four guys want to fly to Florida for a weekend trip and they can almost carry enough fuel given their weights to make the entire trip without refueling. In fact they only need an extra 30 lbs of fuel to make the entire trip. Many people in that situation would go ahead and put the extra fuel on regardless of the fact that that puts them outside of the operating envelope. The fact is that the temptation due to the mimimal amount of overage is just too much to bare.

For this reason alone it is advisable that all perspective aircraft buyers carefully consider their mission. If you have a four member family and two of the four members are young children then a Cessna Skyhawk may be a good fit to your mission. However, if you are a retiree and plan on traveling with your wife and another couple then the Skhawk is definitely not a good fit. It is a good practice to consider your worst case scenario rather than limiting yourself. Realizing that these decisions are often related to economics rather than preference it is suggested that the pilot never push the envelope. You are the keeper of your passengers. In most cases they have no idea about weight and balance and so by overloading a plane you are taking their life into your hands. As you consider them before you take off, also consider them when purchasing an aircraft.