LECTURE 3 WEIGHT CONTROL, EFFECT OF WEIGHT & WEIGHT CHANGE MASS (WEIGHT) & BALANCE 1 MBC SIR ARIFF AMC

IMPORTANT FACTS CRITICAL SITUATION FOR AIRCRAFT TAKE-OFF LANDING STRUCTURAL LIMIT 2 MBC SIR ARIFF AMC

3 To ensure aircraft can fly safely, limitation are set by the design engineer. Maximum Take-Off Weight (MTOW): The maximum permissible weight to conduct a takeoff. Maximum Landing Weight (MLW): The maximum permissible weight to conduct a landing. Maximum Zero Fuel Weight (MZFW): The maximum weight of an aircraft which its structural limits would allow.

REMEMBER !! MBC SIR ARIFF AMC 4 For Take-Off: AUW/TOW ≤ MTOW For Landing: AUW/LW ≤ MLW

All Up Weight (AUW) MBC SIR ARIFF AMC 5 Where, PAYLOAD = Passengers & Cargo FUEL = Flight Fuel + Reserve Fuel DOW = Dry Operating Weight DOW also known as Aircraft Prepared for Service (APS) AUW = DOW + PAYLOAD + FUEL

EXAMPLE #1 Aircraft fly from M to N, given: MTOW = 6180kg MLW = 5740kg MZFW = 5395kg DOW=4400kg Flight Fuel = 767kg Reserve Fuel=250kg Calculate maximum payload that the aircraft is able to carry. 6 MBC SIR ARIFF AMC

SOLUTION EXAMPLE #1 First we must know that the critical situations for aircraft are: During Take-off (MTOW) During Landing (MLW) In term of structural limit. (MZFW) So, we have to consider these situation and calculate for all. 7 MBC SIR ARIFF AMC

Continue.. For Take-Off: AUW/TOW ≤ MTOW We must ensure the All Up Weight during Take-off must equal or less than Maximum Take-Off Weight. Fuel = Flight Fuel + Reserve Fuel. Find the PAYLOAD! AUW = DOW + PAYLOAD + FUEL 8 MBC SIR ARIFF AMC

Continue.. For Landing: AUW/LW ≤ MTOW We must ensure the All Up Weight during Landing must equal or less than Maximum Landing Weight. Fuel = 0. We have used all the fuel during flight. Find the PAYLOAD! AUW = DOW + PAYLOAD + FUEL 9 MBC SIR ARIFF AMC

Continue.. Structural Limit To make sure the structure of aircraft did not fail / damage, we must consider the MAXIMUM ZERO FUEL WEIGHT. Maximum ZERO FUEL WEIGHT Is the Total weight of aircraft WITHOUT FUEL MZFW = AUW - FUEL 10 MBC SIR ARIFF AMC

Comparison... Maximum Payload during take-off = Maximum Payload during landing = Maximum Zero Fuel Weight = Select the lowest Payload as your answer. 11 MBC SIR ARIFF AMC

EXAMPLE #2 Aircraft fly from A to B, given: MTOW = 41,300kg, MLW = 32,250kg DOW = 23,000kg Fuel Flow= 2000kg/hr Mean Speed=455knots (knots = miles/hr) Flight Distance=2150nm (nm = nautical miles) Reserve Fuel=2500kg Calculate maximum payload that the aircraft is able to carry. (**Assume MZFW is not specified) 12 MBC SIR ARIFF AMC

Solution #2 Step 1 : Calculate Flight Time Flight Time = (distance/mean speed) Step 2 : Calculate Flight Fuel Flight Fuel = Flight time x Fuel Flow Step 3 : Same as solution example MBC SIR ARIFF AMC

Comparison... Flight Time = Flight Fuel = Maximum Payload during take-off = Maximum Payload during landing = Maximum Zero Fuel Weight = Select the lowest Payload as your answer. 14 MBC SIR ARIFF AMC

QUIZ # 1 1) For example, if an airplane is flying at a weight of 5,000 lb and the weight of fuel on board is 500 lb. What is the Zero Fuel Weight? 2) Some time later, after 100 lb of fuel has been consumed by the engines, the total weight of the airplane is 4,900 lb and the weight of fuel is 400 lb. What is the Zero Fuel Weight? 15 MBC SIR ARIFF AMC

LECT 3 : WEIGHT CONTROL Weight is a major factor in airplane construction and operation Manufacturers try to make an aircraft as light as they can. But still they have to consider the strength and the safety of aircraft. Excessive weight cause: a) Aircraft efficiency reduce b) Poor performance during flight c) Safety margin available reduce d) Aircraft stability reduce e) Reduce economical profit 16 MBC SIR ARIFF AMC

MK Airlines Flight 1602, a F, crashed while attempting to take off from Halifax Stanfield International Airport on 14 October The aircraft's take-off weight had been incorrectly calculated, and the plane was only briefly airborne before impacting an Earth berm at the end of the runway. The seven-member crew was killed. 17 MBC SIR ARIFF AMC

EFFECTS OF OVERLOADED AIRCRAFT ON PERFORMANCE 1. Higher Takeoff Speed. 2. Longer Takeoff Run 3. Lower Cruising Speeds 4.Less Maneuver 5. Reduced Landing Performance 6. Aircraft Structure Damage 18 MBC SIR ARIFF AMC

Effects Of overloaded airplane 1. Increased Take-off Speed Because more lift is necessary to counter the additional weight, higher speed is necessary to create sufficient lift to attain flight. 2. Longer Take-off Run The increase in necessary speed for takeoff and slower acceleration due to increased weight translates to more runway required to accelerate the airplane to takeoff speed. 19 MBC SIR ARIFF AMC

Effects Of overloaded airplane 3. Lower Cruising Speeds Production of additional lift to counteract greater weight results in an increase in drag. This increased drag reduces the speed at which the airplane travels 4.Less Maneuverability The heavier the airplane is, the less maneuverable it becomes. This is so because the force necessary to change the speed or direction of an object in motion increases with the mass of the object. Maneuverability = aircraft ability to turn away from its previous path. 20 MBC SIR ARIFF AMC

Effects Of overloaded airplane 5. Reduced Landing Performance Overloaded can cause higher approach and landing speeds are necessary. Higher landing speed thus lead to greater landing distance. 6. Aircraft Structure Damage Although the primary concern of an overloaded airplane is its effect on aerodynamic performance, a secondary concern is its effect on structural components, such as landing gears. 21 MBC SIR ARIFF AMC

WEIGHT CHANGES Items that contribute to weight changes: a) Fuel Load b) Cargo and Passenger c) Equipment and Modification Fuel Load The operating weight of an aircraft can be changed by simply altering the fuel load. During flight, fuel burn is normally the only weight change that takes place. As fuel is used, an aircraft becomes lighter and performance is improved. 22 MBC SIR ARIFF AMC

Continue... Cargo & Passenger This weight can’t be altered during flight. But we can monitor this weight before our journey. Equipment & Modification Change of fixed equipment have a major effect upon aircraft weight. Installation extra radios or instrument may affect the weight. Aircraft modification and repairing may contribute to weight change. 23 MBC SIR ARIFF AMC