AIRCRAFT PERFORMANCE EXAM REVISION AND COURSE NOTES
COURSE: AIR TRANSPORT OPERATIONS AND MANAGEMENT
CITY UNIVERSITY LONDON
Exam Paper with Answer n1.
Question 1
FL230 ft: everywhere above this altitude is controlled air space.
a) Describe the concept behind the Central Flow Management Unit (CFMU) in Brussels. (6 marks)
• It’s part of what is called the European Centralized Air Traffic Flow Management System and it’s
operated by EURO Control in Brussels. It affects every flight within controlled air space in Europe.
• It includes a number of different sections, such as:
• FMD (Flight Management Division) responsible for planning and implementation of Flight
Management Measures.
• And FDOD (Flight Data Operations Division), collecting, maintaining and providing data on all flights.
So whenever an aircraft flies over a EU country, this division basically works out how much the airline
needs to pay to each country for the Air Traffic Service & Support they provide.
• IFPS (Integrated Flight Planning System: This is where airlines submit flight plans.
o Concept: What the system does is predict over the whole of Europe where every single
aircraft, according to its flight plan, is going to be in five-minute intervals. Thus it predicts
traffic flows for all traffic control sectors from flight plans submitted by aircraft operators.
o What it aims to achieve is: equitable use of the available air space capacity. All
operators are treated equally and works on a first comes first served and it’s designed to
minimize delays across Europe. It serves a strategic plan to look ahead, forecasting demand
and offering operators alternatives such as: rescheduling or rerouting.
b) Describe the procedures involved in applying for a slot time with the CFMU. This description
should include the various information which has to be included in a slot request, the
procedures carried out by the CFMU in calculating a slot time and the various messages
transmitted between the CFMU and the airline requesting the slot.
• Airlines submit their flight plans to the IFPS (integrated flight planning system) in advance,
including: EOBT – Estimated Off Block Time, Estimated Take Off Time - ETOT, Estimate Time Over –
ETO for major waypoints on proposed route.
• Because it also works in association with Air Traffic Controllers from around Europe, these also provide
CFMU with information on whether they will operating at full capacity or with restrictions
• Based on this, the CFMU computer system can determine how many aircraft will be passing through a
particular air traffic control sector in given 5-minute period based on the flight plans filed. If it detects
that the predicted demand exceeds the legal capacity of a given sector, then what is called a
“Regulation” is enforced.
• A legal limit of a sector is 28 aircraft at once; so whenever demand exceeds capacity the CFMU
system redistribute the demand by issuing delays on flights. Demand is therefore spread out to meet
the allowable limit of capacity. Generally by delaying a number of flights by 5-10 minutes rather than
a single flight by a long time.
• 2 hours before the flight, CFMU allocates a “calculated take-off time”, also know as “slot”, not
necessarily the take-off time the airline requested but airlines must meet this slot time.
• The airline such meet such slot, because if it does not the flight goes at the back of the queue and it
, may be up to 2 hours before one becomes available.
• The system also computes all changes, such as airlines not meeting their allocated slot and/or slot
improvement requests (of 5 mins – minimum), which results on slot improvements proposal or slot
revision message (where airlines must meet original time requested.)
Question 2
(a) Define the following terms:
(i) DOM - Dry Operating Mass: The total mass of the aircraft excluding fuel and traffic load. It includes items
such as: crew and crew baggage, catering and removable passenger service equipment, potable water
and lavatory chemicals, etc.
(ii) TL / PL- Traffic Load / Pay LoadThe total of passenger, baggage and freight. Often referred as “payload”.
The mass that earns the money.
(iii) APS - Aircraft Prepared for Service Mass: Same as DOM but is a more commonly used day-to-day term.
Each individual aircraft has a different mass due to different engine types, seat configuration, onboard
facilities, etc. Some carriers with same facilities on entire fleet thus same APS form for all aircraft.
(iv) BEM/BEW - Basic Empty Mass: the mass of the aircraft with all its basics fixed equipment (eg: engines,
avionics, seats, galleys, etc) + a declared quantity of unusable fuel and oil.
(v) MRM - Maximum Ramp Mass: The maximum approved mass for commencement of ground
manoeuvres. It is usually greater than the MTOM as fuel will be consumed during engine start, taxi and
ground holding. This value changes from airport to airport, as the surface bearing strength of the ramp and
the taxiways has to be considered.
(vi) OM: DOP + Fuel.
(vii) Useful Load: Traffic load + usable fuel
(viii) Zero Fuel Mass: DOM + Traffic Load
(ix) Max Zero Fuel Mass – MZFM: The max permissible mass without usable fuel onboard. This is due to the
structural limits of the aircraf.
(x) TOM – Take Off Mass: the mass of the aircraft including everything at the start of the take-off run.
(xi) MSTOM: Max Structural Take Off Mass: is the max take off mass allowable at the start of the take off run.
(xii) MTM – Max Taxi Mass: Virtually identical to MRM but ignores surface bearing properties.
(xiii) LM – Landing Mass: mass of the aircraft at the moment of touchdown. Whenever an overweight
landing happens, an structural revision must be carried out on the aircraft.
[2 marks for each]
(b) Define the following terms as used in aviation:
Declared speeds are calculated depending on the runway declared distances are. (ASDA, TORA, TODA)
(i) V1: Decision Speed also known as “go/no go speed”. V1 is defined as the maximum speed at which the
rejected takeoff maneuver can be initiated and the airplane stopped within the remaining runway length. If
speed is higher than V1, aircraft must continue to take off and request to land again.
(ii) Vr: Rotation speed. It’s the Speed at which the rotation of the aircraft should be initiated to takeoff
attitude. This speed cannot be less than V1 and if it is greater than V1 and it is found at VR that rotation
cannot be in initiated, then a rejected take off may not be achievable within the remaining runway length.
(iii) V2: Safe Engine Climb Speed: The takeoff safety speed which must be attained at the 35 ft height at the
end of the required runway distance. This is essentially the best one-engine inoperative angle of climb speed
for the airplane and is a minimum speed for flight in that condition until at least 400 ft above the ground.
, [2 marks for each]
(c) Excluding aircraft mass and surface wind, what factors affect the take-off performance of an airliner?
• Air Density as engines will need to
• Rain: take-off acceleration due to water resistance and aquaplaning.
• Snow: breaking performance as it gets compacted under the wheels and they loose grip. So
deceleration can be affected.
• Slash: it produces very high drag against the wheels thus acceleration is greatly affected (Munich air
disaster 50’s) so it’s very dangerous, runways must be cleared of slash before operations continue.
• Surface types: material surfaces can have an effect. Concrete, tarmac, etc, have different effect on
the rolling friction on the tyres.
• Slope of runways: affects acceleration as aircraft fight gravity, downhill is good, uphill is bad.
• Bleed air settings: air taken from the engine for air conditioning, etc.
• Flap settings: by altering the camber, which changes the wing shape, which alters the lift and increase
drag depending on the settings. Drag setting 0 means you are not getting anything out of them, as
you increase the setting, lift will increase too, reducing the take off distance but too much lift will also
produce drag so a balance must be achieved.
[4 marks]
[Total 20 marks]
Question 4
Given the following data:
Airbus A320 with V2500 engines
Basic route statistics
Zero Fuel Mass = 58,500 kg
Route Ground Distance = 1250 nautical miles with average 50kt headwind
Alternate Ground Distance = 300 nautical miles with 30 knot tailwind
Cruising altitude (both segments) = FL 350
The forecast indicates that engine anti-ice will probably be required during the
Alternate segment but NOT the timetabled segment
30 minutes holding fuel = 1200 kg
Taxi fuel = 300kg
use the attached fuel burn charts to calculate the required fuel load to comply with standard JAR
regulations.
1. You begin with aircraft mass when it arrives at the alternate, thus 58,500 kg (ZFM) + 1,200 Kg (HF) =
59,700 kg LM @ alternate upon landing.
2. Now Diversion Fuel is calculated: Alternate ground distance must be converted to air distance. So
you have
300 kt – 270 kt = 30
(-30 * (30/50)) = -18 kt
COURSE: AIR TRANSPORT OPERATIONS AND MANAGEMENT
CITY UNIVERSITY LONDON
Exam Paper with Answer n1.
Question 1
FL230 ft: everywhere above this altitude is controlled air space.
a) Describe the concept behind the Central Flow Management Unit (CFMU) in Brussels. (6 marks)
• It’s part of what is called the European Centralized Air Traffic Flow Management System and it’s
operated by EURO Control in Brussels. It affects every flight within controlled air space in Europe.
• It includes a number of different sections, such as:
• FMD (Flight Management Division) responsible for planning and implementation of Flight
Management Measures.
• And FDOD (Flight Data Operations Division), collecting, maintaining and providing data on all flights.
So whenever an aircraft flies over a EU country, this division basically works out how much the airline
needs to pay to each country for the Air Traffic Service & Support they provide.
• IFPS (Integrated Flight Planning System: This is where airlines submit flight plans.
o Concept: What the system does is predict over the whole of Europe where every single
aircraft, according to its flight plan, is going to be in five-minute intervals. Thus it predicts
traffic flows for all traffic control sectors from flight plans submitted by aircraft operators.
o What it aims to achieve is: equitable use of the available air space capacity. All
operators are treated equally and works on a first comes first served and it’s designed to
minimize delays across Europe. It serves a strategic plan to look ahead, forecasting demand
and offering operators alternatives such as: rescheduling or rerouting.
b) Describe the procedures involved in applying for a slot time with the CFMU. This description
should include the various information which has to be included in a slot request, the
procedures carried out by the CFMU in calculating a slot time and the various messages
transmitted between the CFMU and the airline requesting the slot.
• Airlines submit their flight plans to the IFPS (integrated flight planning system) in advance,
including: EOBT – Estimated Off Block Time, Estimated Take Off Time - ETOT, Estimate Time Over –
ETO for major waypoints on proposed route.
• Because it also works in association with Air Traffic Controllers from around Europe, these also provide
CFMU with information on whether they will operating at full capacity or with restrictions
• Based on this, the CFMU computer system can determine how many aircraft will be passing through a
particular air traffic control sector in given 5-minute period based on the flight plans filed. If it detects
that the predicted demand exceeds the legal capacity of a given sector, then what is called a
“Regulation” is enforced.
• A legal limit of a sector is 28 aircraft at once; so whenever demand exceeds capacity the CFMU
system redistribute the demand by issuing delays on flights. Demand is therefore spread out to meet
the allowable limit of capacity. Generally by delaying a number of flights by 5-10 minutes rather than
a single flight by a long time.
• 2 hours before the flight, CFMU allocates a “calculated take-off time”, also know as “slot”, not
necessarily the take-off time the airline requested but airlines must meet this slot time.
• The airline such meet such slot, because if it does not the flight goes at the back of the queue and it
, may be up to 2 hours before one becomes available.
• The system also computes all changes, such as airlines not meeting their allocated slot and/or slot
improvement requests (of 5 mins – minimum), which results on slot improvements proposal or slot
revision message (where airlines must meet original time requested.)
Question 2
(a) Define the following terms:
(i) DOM - Dry Operating Mass: The total mass of the aircraft excluding fuel and traffic load. It includes items
such as: crew and crew baggage, catering and removable passenger service equipment, potable water
and lavatory chemicals, etc.
(ii) TL / PL- Traffic Load / Pay LoadThe total of passenger, baggage and freight. Often referred as “payload”.
The mass that earns the money.
(iii) APS - Aircraft Prepared for Service Mass: Same as DOM but is a more commonly used day-to-day term.
Each individual aircraft has a different mass due to different engine types, seat configuration, onboard
facilities, etc. Some carriers with same facilities on entire fleet thus same APS form for all aircraft.
(iv) BEM/BEW - Basic Empty Mass: the mass of the aircraft with all its basics fixed equipment (eg: engines,
avionics, seats, galleys, etc) + a declared quantity of unusable fuel and oil.
(v) MRM - Maximum Ramp Mass: The maximum approved mass for commencement of ground
manoeuvres. It is usually greater than the MTOM as fuel will be consumed during engine start, taxi and
ground holding. This value changes from airport to airport, as the surface bearing strength of the ramp and
the taxiways has to be considered.
(vi) OM: DOP + Fuel.
(vii) Useful Load: Traffic load + usable fuel
(viii) Zero Fuel Mass: DOM + Traffic Load
(ix) Max Zero Fuel Mass – MZFM: The max permissible mass without usable fuel onboard. This is due to the
structural limits of the aircraf.
(x) TOM – Take Off Mass: the mass of the aircraft including everything at the start of the take-off run.
(xi) MSTOM: Max Structural Take Off Mass: is the max take off mass allowable at the start of the take off run.
(xii) MTM – Max Taxi Mass: Virtually identical to MRM but ignores surface bearing properties.
(xiii) LM – Landing Mass: mass of the aircraft at the moment of touchdown. Whenever an overweight
landing happens, an structural revision must be carried out on the aircraft.
[2 marks for each]
(b) Define the following terms as used in aviation:
Declared speeds are calculated depending on the runway declared distances are. (ASDA, TORA, TODA)
(i) V1: Decision Speed also known as “go/no go speed”. V1 is defined as the maximum speed at which the
rejected takeoff maneuver can be initiated and the airplane stopped within the remaining runway length. If
speed is higher than V1, aircraft must continue to take off and request to land again.
(ii) Vr: Rotation speed. It’s the Speed at which the rotation of the aircraft should be initiated to takeoff
attitude. This speed cannot be less than V1 and if it is greater than V1 and it is found at VR that rotation
cannot be in initiated, then a rejected take off may not be achievable within the remaining runway length.
(iii) V2: Safe Engine Climb Speed: The takeoff safety speed which must be attained at the 35 ft height at the
end of the required runway distance. This is essentially the best one-engine inoperative angle of climb speed
for the airplane and is a minimum speed for flight in that condition until at least 400 ft above the ground.
, [2 marks for each]
(c) Excluding aircraft mass and surface wind, what factors affect the take-off performance of an airliner?
• Air Density as engines will need to
• Rain: take-off acceleration due to water resistance and aquaplaning.
• Snow: breaking performance as it gets compacted under the wheels and they loose grip. So
deceleration can be affected.
• Slash: it produces very high drag against the wheels thus acceleration is greatly affected (Munich air
disaster 50’s) so it’s very dangerous, runways must be cleared of slash before operations continue.
• Surface types: material surfaces can have an effect. Concrete, tarmac, etc, have different effect on
the rolling friction on the tyres.
• Slope of runways: affects acceleration as aircraft fight gravity, downhill is good, uphill is bad.
• Bleed air settings: air taken from the engine for air conditioning, etc.
• Flap settings: by altering the camber, which changes the wing shape, which alters the lift and increase
drag depending on the settings. Drag setting 0 means you are not getting anything out of them, as
you increase the setting, lift will increase too, reducing the take off distance but too much lift will also
produce drag so a balance must be achieved.
[4 marks]
[Total 20 marks]
Question 4
Given the following data:
Airbus A320 with V2500 engines
Basic route statistics
Zero Fuel Mass = 58,500 kg
Route Ground Distance = 1250 nautical miles with average 50kt headwind
Alternate Ground Distance = 300 nautical miles with 30 knot tailwind
Cruising altitude (both segments) = FL 350
The forecast indicates that engine anti-ice will probably be required during the
Alternate segment but NOT the timetabled segment
30 minutes holding fuel = 1200 kg
Taxi fuel = 300kg
use the attached fuel burn charts to calculate the required fuel load to comply with standard JAR
regulations.
1. You begin with aircraft mass when it arrives at the alternate, thus 58,500 kg (ZFM) + 1,200 Kg (HF) =
59,700 kg LM @ alternate upon landing.
2. Now Diversion Fuel is calculated: Alternate ground distance must be converted to air distance. So
you have
300 kt – 270 kt = 30
(-30 * (30/50)) = -18 kt
