P&L W&B Flashcards
CG checks at TAXI and ZFW are required because as fuel is burnt in flight the CG
moves!
Advantages of using stabiliser trim are that
it reduces drag, preserves elevator travel and permits a smaller elevator
The MAC of a swept wing is defined being equivalent to the chord of an unswept rectangular wing of the same area, or the chord through
the centroid of the area.
The %of MAC is the distance from back along the chord from the
the leading edge
The representation of the aircraft CoG as a %of MAC permits comparison of the CG relative to the wing.. .. .
Centre of Pressure!
The distance between the CP and CoG determines the magnitude of the .. ..
pitching moments which must be balanced with pitch trim for take-off!
When loading a tricycle undercarriage aircraft, cargo should be first loaded into the front compartments and pax into
centre/front zones to prevent over balancing!
The nosed down pitching moment produced by a rear CG produces is weak and produces less ‘induced drag’ than a FWD CG.
FWD CG’s require larger stabaliser A….
stabaliser AOA’s for the same speed –> which produces more induced drag compared to a rear CG.
Less drag is produced for a given weight and speed with a …..
Rear CG position!
With a rear CG, the arm from CG to tail plane is short so the tailplane is
LESS effective, consequently in the cruise there will be reduced longitudnal stability and light elevator forces to effect pitch changes. .
When fuel is added as ballast
it is considered UNUSABLE and the BW needs to be increaseed by the weight of the ballast fuel!
THIS REDUCES PAYLOAD capacity!
Max PAX - 138
Plus 6 Cabin Crew
- 144 seats -
Empty weight includes equiptment whcih has a fixed location and is actually on the aircraft when it is weighed, inlcuding…..
ALL engine oil, hydraulic fluid & unusable fuel!
EW + Operational Items =
BEW
Operational Items include cockpit documentation, cabin equiptment as well as
crew and galley provision!
BEW does not include
Usable-fuel OR Payload!
The CG datum on the 727 is located just forward of the
main gear
If adding weight to a station causes a nose down effect,
its a negative (-) adjustment,
If nose up, its a positive (+) adjustment!
Flight fuel is the amount of fuel to be consumed from take off to first intended landing point PLUS
400 kg allowance for approach and manoeuvring!
If extra items are carried in the cabin with special authorisation, the load which must not be exceeded is…
87kg/SEAT!
THIS SEAT MAY NOT BE USED FOR PASSENGER!
and the IU effect is accounted for on the load sheet.
Over wing fuel capacity is less than underwing due to dihedral. The filling points are lower than the wing tips so there will be
no fuel in the wing tips
Jet A1 is less dense than water (.79 SG). As temperature increases, SG
Decreases as fuel becomes less dense and expands!
If fuel expands too much, there may be insufficient volume available in the tanks to provides the range for long flights.
The total fuel capacity of all tanks together in the 727 is
29,094kg!
Any time fuel load exceeds 15,924kg,
the first 3629kg of fuel alsways comes from TANK 2!
Looking at the balance sheet, left is forward and right is rearward movement of the
CoG
If operating with a inop aft fuel boost pump in TANK 2, 5443 kg of fuel must be left in the tanks at all times to ensure the FORWARD pump pick up will remain
covered during all normal flight attitudes to preven starvation!
IU changed produced by the ballasting methods are always NEGATIVE, meaning they are used to correct rear CG problems at
at ZFW
When fuel is added as balast, it is considered
UNUSABLEat all times!
Regarding last minute passenger adjustments,
both TAXI and ZFR CoG positions
MUST BE encloses by the last minute line!
