For both engines, this is 52.83 × 2 = 105.66 lb/minute. The engines burn 105.66 lbs of fuel per min for 19 minutes  (the duration of the dump), which calculates to 2007.54  pounds of fuel burned between the beginning of the dump  and touchdown. Most large aircraft are approved for a greater weight for  takeoff than for landing. To make it possible for them to  return to landing soon after takeoff, a fuel jettison system is  sometimes installed. It is important in an emergency situation  that the flight crew be able to dump enough fuel to lower the  weight to its allowed landing weight. This is done by timing  the dumping process. In this example, the aircraft has two engines operating and  these specifications apply The Beech 1900 is a typical commuter category airplane that  can be configured to carry passengers or cargo.  Figure 9-40 shows the loading data of this type of airplane in the  passenger configuration As this airplane is prepared for flight, a manifest is prepared. [Figure 9-41] Figure 9-37.  Determining the amount of fuel burned from the  beginning of the dump to touchdown. Figure 9-36.  Determining the amount of weight the aircraft must  lose to reach the maximum allowable landing weight. Figure 9-39.  Determine the time needed to dump fuel. Weight and Balance of Commuter Category  Airplanes Determining the Loaded Weight and CG Determining Fuel Dump Time in Minutes Figure 9-38.  Determining the amount of fuel needed to dump. 2.  Determine the amount of fuel burned from the  beginning of the dump to touchdown.  [Figure 9-37] 1.  Determine the amount of weight the aircraft must  lose to reach the maximum allowable landing weight.  [Figure 9-36] 4.  Determine the time needed to dump this amount of  fuel by dividing the number of pounds of fuel to dump  by the dump rate.  [Figure 9-39] 3.  Determine the amount of fuel needed to dump by  subtractingtheamountof fuelburned duringthedump  from the required weight reduction.  [Figure 9-38] To calculate the fuel dump time in minutes: Average fuel flow during Cruise weight................................................. 171,000 lb Maximum landing weight.............................. 142,500 lb Time from start of dump to landing.............. 19 minutes Dumping and descent .............................3,170 lb/hr/eng Fuel dump rate.......................................2,300 lb/minute 28,500.00 lb required weight reduction – 2,007.54 lb fuel burned after start of dumping 26,492.46 lb fuel to be dumped = 11.52 minutes 26,492.46 2,300 171,000 lb cruise weight – 142,500 lb maximum landing weight 28,500 lb required reduction Fuel flow = 3,170 lb/hr/engine 60 = 52.83 lb/min engine 9-12