Mass and Weight Limits Flashcards
What are controlling regulations for Mass and Balance?
EU-OPS
What do the EU-OPS specify for Mass and Balance?
- Loading, mass and CG of the aeroplane must comply with:
o Limitations in the AFM or Operations Manual, whichever is more restrictive - Set out requirements to be included in the Operations Manual
What’s the Basic Empty Mass (BEM) or Basic Mass (BM)?
The mass of the aircraft with:
- Basic equipment
- Unusable fuel and other fluids
- Lubricating oil in the engines
- Fire extinguishers
- Pyrotechnics
- Emergency oxygen equipment
- Supplementary electronic equipment
What’s the Variable load (VL)?
Often referred as the “operational items”, consists of:
- Crew
- Crew’s baggage
- Removable equipment that is required for that flight, for example:
o Catering
o Passenger service equipment
o Food and beverages
o Potable water
o Lavatory chemicals
What’s the Dry Operating Mass (DOM)?
BM + VL
What’s the Useful or Disposable Load?
- Traffic Load:
o Passengers
o Their baggage
o Their freight - The usable fuel
- The usable oil where appropriate
What’s the Traffic Load?
It’s the total mass of:
- Passengers
- Baggage
- Cargo
- Carry-on specialist equipment including any ballast
- Non-revenue load
o Spare parts
o Positioning crew
What’s the Zero Fuel Mass (ZFM) ? What’s the Maximum Zero Fuel Mass (MZFM)?
Zero Fuel Mass is the total mass of the aircraft NOT considering the usable fuel
- DOM + Traffic Load
Maximum Zero Fuel Mass (MZFM) is a structural limit in the wing roots:
- In some aircraft the mass of fuel in fuselage tanks is included in the ZFM
- Only take account of fuselage fuel in ZFM calculations when specifically instructed to do so
What’s the Operating Mass?
DOM of aircraft plus fuel but without traffic load
- It can be thought as the wet operating mass as opposed to the DOM defined earlier
What the taxy mass? What’s the Maximum Taxy MAss (MTM)?
Taxy Mass (TM) is the mass of the aircraft before engine start, also known as Ramp Weight or Ramp mass and is sometimes defined as:
- Mass at the start of the taxy
Maximum Taxy Mass (MTM) is a structural limit:
- Greatest mass at which the aircraft can be taxyed
What’s the Take-off mass?
It’s the mass of the aircraft at the start of the take-off run
- It may be affected by performance calculations
What’s the Maximum Structural TOM?
It is a structural limit defined as:
- Maximum mass that the aircraft can take-off at anywhere in the world in the most favourable conditions in accordance with Certificate of Airworthiness
- Usually the MTM minus Standard Taxy Fuel
o Can be referred to as the Maximum Take-off mass authorized (MTMA)
What’s the allowed Take-off Mass?
It’s the mass taking into consideration:
- All possible limitations for take-off including:
o Restrictions caused by the Regulated Take-off Mass and
o Regulated Landing Mass
What’s the Performance Limited Take-off and Landing Mass (PLTOM)? What’s the Performance Limited Landing Mass (PLLM)?
Performance Limited Take-off and Landing Mass (PLTOM) is the take-off mass by departure airfield considerations such as:
- Runway length
- Obstacles
- Temperature and
- Altitude
Performance Limited Landing Mass (PLLM) is the landing mass limited by similar destination airfield considerations, it is a limit derived from Performance Calculations
What’s the Regulated Take-Off Mass?
Is the lower of:
- Maximum structural TOM and the PLTOM
What’s the Landing Mass?
It is the mass of the aircraft as it crosses the threshold on landing
What’s the Maximum Structural Landing Mass (MSLM)?
It’s a structural limit
What’s the Regulated Landing Mass (RLM)?
It is the lower of:
- MSLM and PLLM
What’s the All Up Mass (AUM) or the All Up Weight (AUW)?
It’s the total mass or weight of the aircraft at a particular time
What’s the Maximum All Up Mass (MAUM)?
MAUM is the greatest mass that an aircraft can be loaded to. Although the definitions are different, the MAUM and the Maximum Taxy Mass describe the same mass.
Can the Maximum In-Flight Mass exceed the MTOM? Can the airborn weight be greater than TOM?
- It can, in theory, exceed the MTOM because the forces in flight and the limitations derived from them differ from those experienced during the take-off roll.
- In practice, however, the airborne weight can never be greater than TOM unless the aircraft has been refueled in flight.
What’s Maximum Operational Passenger Seating Configuration (MOPSC)?
What does it exclude?
For what is it established?
The MOPSC is the maximum passenger seating capacity of an individual aircraft
- Excluding crew seats
- Established for operational purposes and specified in the operations manual
How often do you have to weight an aircraft if it is considered individually?
4 years
What if fleet advantages are used?
9 years
What are the weighting conditions if aeroplanes are transferred between EASA operators?
They do not need to be weighted unless 4 years have passed since the last time the weights were checked
What must the operator account for and document in this case? How can they do this?
Accumulated effects of modifications and repairs between weightings.
By either weighting the equipment added and removed, or by using standard masses
What’s the margin they can afford to a change of the DOM?
By > 0.5% of the MLM
CG shifts > 0.5% of the MAC
What happens if these margins are not respected?
Aircraft must be reweighted and CG re-established
Exceptionally, this can be done by calculation, but the operator has to justify the method used to the Authority
By whom must the weighting be carried out in the Aircraft Weighting Conditions?
o Manufacturer
o Approved Maintenance Organization
Which normal precautions must be taken?
o Checking for completeness of the aeroplane and equipment:
Established by reference to an equipment list
o Determining that fluids are properly accounted for
o Ensuring aeroplane is clean
o Ensuring that weighting is accomplished in an enclosed building (important)
o Three points of support
How must the weighting equipment be?
o Properly calibrated
o Zeroed
o Used in accordance with the manufacturer’s instructions
o Must enable the mass of the aeroplane to be established accurately
By whom and when do the scales need to be calibrated?
o Calibrated by:
The manufacturer
Civil deparment of weights and measures or
Appropriately authorized organization
o Calibrated within:
Within 2 years or
Within a time period defined by:
* Manufacturer or
* The Weighting equipment, whichever is less
What needs to be done once the BEM and CG have been established?
How are the changes tracked?
o It is recorded
o Changes are tracked in a document known as the “Weighting Schedule”
Form part of the aircraft technical log
To whom must the manufacturer give the weighting report?
To the operator
What must the operator do with the weighting report? What’s the operator’s responsibility?
Add the variable load to establish the DOM
It is the operator’s responsibility to ensure that the aircraft has been weighed correctly
Where are the CG limits of the aircraft found?
In its Operating Data Manual (ODM)
What’s the name of the equipment used to weight the aircraft? What must be done to find the net weight?
Tare Unit:
o Must be subtracted from the scale reading to find the net weight
What’s the unit of weighting points?
What does it allow?
What does also need to be listed in the weighting report?
Stations:
o Allows calculation of the moment and the CG position
- Missing Equipment or variations to the BEM
What operators work out if they have a fleet that meets certain criteria?
A single DOM and CG position
According to the EU-OPS:
Tolerances
1 What’s the margin of a DOM of any aeroplane or the calculated DOM of any aeroplane of a fleet for that aeroplane to be omitted from that fleet?
2 What happens if aeroplane’s mass is within DOfM tolerance but its CG position falls outside the permitted fleet tolerance?
3 What happens if there’s a physical accurately accountable difference that causes exceedance of the fleet tolerances?
4 What happens if no MAC is published?
1
> ± 0.5% of MSLM from the established Dry Operating Fleet Mass (DOfM) or
CG position varies by more than ± 0.5% of the MAC from the fleet’s CG
2
Aeroplane may still be operated under the applicable DOfM but with an individual CG position
3
Aeroplane may be maintained in the fleet provided that appropriate corrections are applied to the mass and/or CG
4
i. Aircraft must be operated with their individual mass and CG position values or
ii. Must be subjected to a special study approval
According to the EU-OPS:
Use of fleet values
1 What happens if after weighting of an aeroplane, or if any change occurs in the aeroplane equipment or configuration?
2 What happens if the aeroplane is not weighted since last fleet mass evaluation?
3 How can an aeroplane be added with flee values?
4 When do fleet values need to be updated?
1
i. Operator must verify that this aeroplane falls within the tolerances specified in subparagraph (i) above (tolerances)
2
i. Can be kept in a fleet operated with fleet values, provided that
a. Individual values are revised by computation and
b. Stay within the tolerances defined in subparagraph (i) above
ii. If individual values no longer fall within the permitted tolerances, the operator must either determine:
a. New fleet values fulfilling the conditions of sub-paragraph (i) above
b. or operate the aeroplanes not falling within the limits with their individual values
3
i. Operator must verify by weighting or computation that its actual values fall within the tolerances specified in subparagraph (i) above
4
Fleet values must be updated at least at the end of each fleet mass evaluation
When must the operator weight during fleet mass evaluations?
Which aeroplanes need to be selected?
What’s the interval between 2 fleet mass evaluations?
How must the CG be expressed?
When must fleet masses be recalculated? What about individual aircraft?
- See table in BGL
- Aeroplanes in the fleet which have not been weighed for the longest time must be selected
- Must not exceed 48 months
- CG must be expressed as %MAC
- Every 4 years for fleet masses and every 9 years for individual aircraft
