Civil Subsonic Jet Aircraft Statistics (Sizing Parameters and Regression Analysis)
This section examines the statistics of current aircraft geometry and weight to identify aircraft sizing parameters. Regression analyses are carried out to demonstrate a pattern as proof of expectations. With available statistics, aircraft can be roughly sized to meet specifications. This is the starting point; Chapter 11 discusses formal sizing to finalizing aircraft configuration.
(a) Lower capacity (b) Higher capacity
Figure 4.5. Number of passengers versus MTOM
Definitions of various types of aircraft mass (i. e., weight) are provided in Chapter 8; some are required in this section, as follows (payload could be passengers and/or cargo):
MEM: manufacturer’s empty mass – the finished aircraft mass rolls out from
the factory line
OEM: operator’s empty mass = MEM + crew + consumable – it is now
ready for operation
MTOM: maximum takeoff mass = OEM + payload + fuel – loaded to maximum design mass
MEM is the design outcome from catering to the MTOM, in which fuel load and payload are traded. The trade-off between payload (i. e., passenger) and fuel is at the operator’s discretion, who has the choice to trade between them (see Chapter 13). Keeping the MTOM invariant, the operator can offload some passengers to increase the fuel load to the extent that the tankage capacity would allow a farther flying distance. Conversely, fuel could be offloaded to a shorter range, allowing an increase in passengers to the extent the aircraft can accommodate. Mass per passenger is revised to 100 kg (220 lb) from the earlier value of 90 kg (200 lb), which includes baggage allowance; there could be additional cargo load.