SECTION 6
WEIGHT AND BALANCE
PA-44-180, SEMINOLE
TABLE OF CONTENTS
SECTION 6
WEIGHT AND BALANCE
Paragraph
No.
Page
No.
6.1
General.....
6-1
6.3
Airplane Weighing Procedure
6-2
6.5
Weight and Balance Data Record
6-5
6.7
Weight and Balance Determination for Flight
.
6-9
6.9
Instructions for Using the Weight and Balance Plotter
.
6-15
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ISSUED: JULY 12, 1995
REPORT: VB-1616
6-i
SECTION 6
PA-44-180, SEMINOLE
WEIGHT AND BALANCE
SECTION 6
WEIGHT AND BALANCE
6.1 GENERAL
In order to achieve the performance and flying characteristics which are
designed into the airplane, it must be flown with the weight and center of
gravity (CO.) position within the approved operating range (envelope).
Although the airplane offers flexibility of loading, it cannot be flown with the
maximum number of adult passengers, full fuel tanks and maximum baggage.
With the flexibility comes responsibility. The pilot must ensure that the
airplane is loaded within the loading envelope before he makes a takeoff.
Misloading carries consequences for any aircraft. An overloaded airplane
will not take off, climb or cruise as well as a properly loaded one. The heavier
the airplane is loaded, the less climb performance it will have.
Center of gravity is a determining factor in flight characteristics. If the
e.G. is too far forward in any airplane, it may be difficult to rotate for takeoff
or landing. If the CO. is too far aft, the airplane may rotate prematurely on
takeoff or tend to pitch up during climb. Longitudinal stability will be reduced.
This can lead to inadvertent stalls and even spins; and spin recovery becomes
more difficult as the center of gravity moves aft of the approved limit.
A properly loaded airplane, however, will perform as intended. This
airplane is designed to provide performance within the flight envelope. Before
the airplane is delivered, it is weighed, and a basic empty weight and CO.
location is computed (basic empty weight consists of the standard empty
weight of the airplane plus the optional equipment). Using the basic empty
weight and e.G. location, the pilot can determine the weight and C.G. position
for the loaded airplane by computing the total weight and moment and then
determining whether they are within the approved envelope.
ISSUED: JULY 12, 1995
REPORT: VB-1616
6-1
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SECTION 6
WEIGHT AND BALANCE
PA·44.180, SEMINOLE
6.1 GENERAL (Continued)
The basic empty weight and C.G. location are recorded in the Weight and
Balance Data Form (Figure 6-5) and the Weight and Balance Record (Figure
6-7). The CUITentvalues should always be used. Whenever new equipment is
added or any modification work is done, the mechanic responsible for the work
is required to compute a new basic empty weight and CG. position and to
write these in the Aircraft Log Book and the Weight and Balance Record. The
owner should make sure that it is done.
)
A weight and balance calculation is necessary in determining how much
fuel or baggage can be boarded so as to keep within allowable limits. Check
calculations prior to adding fuel to ensure against overloading.
The following pages are forms used in weighing an airplane in production
and in computing basic empty weight, CG. position, and useful load. Note that
the useful load includes usable fuel, baggage, cargo and passengers. Following
this is the method for computing takeoff weight and CO.
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6.3 AIRPLANE WEIGHING PROCEDURE
r
At the time of licensing, provides each airplane with the basic empty
weight and center of gravity location. This data is supplied by Figure 6-5.
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The removal or addition of equipment or airplane modifications can affect
the basic empty weight and center of gravity. The following is a weighing
procedure to determine this basic empty weight and center of gravity location:
r
Be certain that all items checked in the airplane equipment
list are installed in the proper location in the airplane.
(2) Remove excessive dirt, grease, moisture, and foreign items
such as rags and tools, from the airplane before weighing.
(3) Defuel airplane. Then open all fuel drains until all remaining
fuel is drained. Operate each engine until all undrainable fuel
is used and engine stops. Then add the unusable fuel (2.0
gallons total. 1.0 gallon each wing).
REPORT: VB·1616
6-2
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(a) Preparation
(I)
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ISSUED: JULY 12, 1995
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SECTION 6
PA-44-180, SEMINOLE
WEIGHT AND BALANCE
6.3 AIRPLANE WEIGHING PROCEDURE (Continued)
CAUTION
I~
Whenever the fuel system is completely drained
and fuel is replenished it will be necessary to run
the engines for a minimum of 3 minutes at 1000
RPM on each tank to ensure no air exists in the
fuel supply lines.
(4) Fill with oil to full capacity.
(5) Place pilot and copilot seats in fourth (4th) notch, aft of
forward position. Put flaps in the fully retracted position and
all control surfaces in the neutral position. Tow bar should be
in the proper location and entrance and baggage door closed.
(6) Weigh the airplane inside a closed building to prevent errors
in scale readings due to wind.
(b) Leveling
(I) With airplane on scales, block main gear oleo pistons in the
fully extended position.
(2) Level airplane (refer to Figure 6-3) deflating nose wheel tire,
to center bubble on level.
(c) Weighing- Airplane Basic Empty Weight
(1) With the airplane level and brakes released, record the weight
shown on each scale. Deduct the tare, if any, from each
reading.
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ISSUED: JULY 12, 1995
REPORT: VB-1616
6-3
SECTION 6
WEIGHT AND BALANCE
PA-44-180, SEMINOLE
Scale
Reading
Scale Position and Symbol
Nose Wheel
(N)
Right Main Wheel
(R)
Left Main Wheel
(L)
Basic Empty Weight,
(as Weighed)
(T)
Tare
Net
Weight
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WEIGHING FORM
Figure 6-1
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Nacelle
U (Top View)
I
Fairing (Outboard of Nacelle)
Level Points
(Fuselage Left Side)
Wing Leading Edge
R+L
A
1---
B---o.~1
The datum is 78.4 inches
A=
B
=
ahead of the wing leading
edge at Wing Station 106.
8.7"
109.7"
LEVELING DIAGRAM
Figure 6-3
REPORT: VB-1616
6-4
ISSUED: JULY 12, 1995
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PA-44-180, SEMINOLE
WEIGHT
SECTION 6
AND BALANCE
6.3 AIRPLANE WEIGIDNG PROCEDURE (Continued)
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(d) Basic Empty Weight Center of Gravity
(1) The Leveling Diagram geometry (Figure 6-3) applies to the
PA-44-180 airplane when it is level. Refer to Leveling
paragraph 6.3 (b).
(2) The basic empty weight center of gravity (as weighed
including optional equipment, full oil and unusable fuel) can
be determined by the following formula:
c.G. Ann
= N (A) + CR+ L)
(B)
inches
T
Where:
6.5 WEIGHT
,~
T
= N +R +L
AND BALANCE DATA AND RECORD
The Basic Empty Weight, Center of Gravity Location and Useful Load
listed in Figure 6-5 are for the airplane as delivered from the factory. These
figures apply only to the specific airplane serial number and registration
number shown.
The basic empty weight of the airplane as delivered from the factory has
been entered in the Weight and Balance Record (Figure 6-7). TIllS form is
provided to present the current status of the airplane basic empty weight and
a complete
history of previous
modifications.
Any change to the
permanently installed equipment or modification which .affects weight or
moment must be entered in the Weight and Balance Record.
ISSUED: JULY 12,1995
REPORT:
VB-1616
6-5
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SECTION 6
WEIGHT AND BALANCE
PA-44-180, SEMINOLE
MODEL PA-44-1S0, SEMINOLE
Airplane Serial Number
4496211
Registration Number
N380U
Date
07125/05
AIRPLANE BASIC EIv1PTY WEIGHT
I
C.G. Ann
x (Inches Aft
of Datum)
Weight
(Lbs)
Item
Actual
Standard Empty Weight*
T
=
Moment
(In-Lbs)
2596.9
85.8163
222856.4
55.4
115.2563
6385.2
2652.3
86.4312
229241.6
Comptttefi
Optional Equipment
Basic Empty Weight
*The standard empty weight includes full oil capacity and 2.0 gallons of
unusable fuel.
AIRPLANE USEFUL LOAD - NORMAL CATEGORY OPERATION
(Gross Weight) - (Basic Empty Weight)
(3800 lbs.) - (
2652.3
lbs.)
=
=
1147.7
Useful Load
lbs.
THIS BASIC EMPTY WEIGHT, C.G. AND USEFUL LOAD ARE
FOR THE AIRPLANE
AS LICENSED
AT THE FACTORY. REFER
TO APPROPRIATE
AIRCRAFT
HAVE BEEN MADE.
WEIGHT
RECORD
AND BALANCE
WHEN
ALTERATIONS
DATA FORM
Figure 6-5
REPORT:
6-6
VB-1616
ISSUED: JULY 12, 1995
)
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Serial Number
PA-44-180
c:l
4496211
M
Registration Number N380U
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Empty Weight
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(Lb.)
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As Delivered
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SECTION 6
WEIGHT AND BALANCE
I
,,;.
PA-44-180, SEMINOLE
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~~--------+-------------------------------------"<t
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Figure 6-7 (Continued)
ISSUED: JULY 12, 1995
WEIGHT AND BALANCE RECORD (Continued)
REPORT: VB-1616
6-8
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SECTION 6
PA-44-180, SEMINOLE
WEIGHT AND BALANCE
6.7 WEIGHT AND BALANCE DETERMINATION
FOR FLIGHT
(a) Add the weight of all items to be loaded to the basic empty weight.
(b) Use the Loading Graph (Figure 6-13) to determine the moment of all
items to be carried in the airplane.
(c) Add the moment of all items to be loaded to the basic empty weight
moment.
(d) Divide the total moment by the total weight to determine the C.G.
location.
(e) By using the figures of item (a) and item (d) (above), locate a point on
the C.G. range and weight graph (Figure 6-15). If the point falls
within the e.G. envelope, the loading meets the weight and balance
requirements.
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ISSUED: JULY 12, 1995
REPORT: VB·1616
6-9
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SECTION 6
WEIGHT AND BALANCE
PA·44.180, SEMINOLE
6.7 WEIGHT AND BALANCE
(Continued)
DETERMINATION
Weight
(Lbs)
Basic Empty Weight
Pilot and Front Passenger
Passengers (Rear Seats)
340.0
340.0
FOR FLIGHT
Arm Aft
Datum
(Inches)
80.5
118.1
Fuel (l08 Gallon Maximum Usable)
95.0
Baggage (200 Lb. Limit)
142.8
Moment
(In-Lbs)
27370
40154
Ramp Weight (3816 Lbs. Max.)
Fuel Allowance for Engine
Start, Taxi & Runup
-16.0
95.0
-1520
Take-off Weight (3800 Lbs. Max.)
The center of gravity (e.G.) for the take-off weight of this sample loading
problem is at
inches aft of the datum line. Locate this point (
) on
the CiG. range and weight graph. Since this point falls within the weight e.G. envelope, this loading meets the weight and balance requirements.
Take-off Weight
Minus Estimated Fuel Burn-off
(climb & cruise) @ 6.0 Lbs/Gal.
95.0
Landing Weight
Locate the center of gravity of the landing weight on the e.G. range and
weight graph. Since this point falls within the weight- e.G. envelope, the
loading may be assumed acceptable for landing.
IT IS THE RESPONSIBILITY
OF THE PILOT AND AIRCRAFT
TO ENSURE THAT THE AIRPLANE
TIMES.
OWNER
IS LOADED PROPERLY AT ALL
,.,.--......
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SAMPLE LOADING PROBLEM
Figure 6-9
REPORT: VB·1616
6·10
ISSUED: JULY 12, 1995
,
SECTION 6
WEIGHT AND BALANCE
PA.44.180, SEMINOLE
6.7 WEIGHT
AND BALANCE DETERMINATION
FOR FLIGHT
(Continued)
Weight
(Lbs)
Arm Aft
Datum
(Inches)
Moment
(In-Lbs)
Basic Empty Weight
Pilot and Front Passenger
80.5
Passengers (Rear Seats)
118.1
Fuel (108 GaIIon Maximum Usable)
95.0
Baggage (200 Lb. Limit)
Ramp Weight (3816 Lbs. Max.)
142.8
Fuel AIIowance for Engine
Start, Taxi & Runup
-16.0
95.0
-1520
Take-off Weight (3800 Lbs. Max.)
The center of gravity (e.G.) for the take-off weight of this
loading
problem is at
inches aft of the datum line. Locate this point (
) on
the e.G. range and weight graph. If this point falls within the weight e.G. envelope, this loading meets the weight and balance requirements.
Take-off Weight
Minus Estimated Fuel Burn-off
(climb & cruise) @ 6.0 Lbs/Gal.
95.0
Landing Weight
Locate the center of gravity of the landing weight on the e.G. range and
weight graph. If this point falls within the weight- C.G. envelope, the
loading may be assumed acceptable for landing.
IT IS THE RESPONSIBILITY OF THE PILOT AND AIRCRAFT OWNER
TO ENSURE THAT THE AIRPLANE IS LOADED PROPERLY AT ALL
TIMES.
WEIGHT AND BALANCE LOADING FORM
Figure 6-11
ISSUED: JULY 12, 1995
REPORT: VB·1616
6·11
SECTION 6
WEIGHT AND BALANCE
PA-44-180, SEMINOLE
(\
THIS PAGE INTENTIONALLY
REPORT:
6-12
VB-1616
LEFT BLANK
ISSUED: JULY 12, 1995
SECTION 6
WEIGHT AND BALANCE
PA-44-180, SEMINOLE
700
110
100
550
100
410
~400
Z
:>
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g lIO
~
~300
~
c
~ 280
..•
~;.
200
110
100
.+
1
10
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0
0
II
10
II
20
21
30
31
40
41
10
III
.0
II
MOMENT 11000 IPOUNOI-INCHElI
LOADING GRAPH
Figure 6-13
ISSUED: JULY 12, 1995
REPORT: VB-1616
6-13
SECTION 6
WEIGHT AND BALANCE
3800
PA-44-180, SEMINOLE
MAX. T.O. AND
89
V
88
90
LANDING WEIGHT
3700
86/,
3400
-~~
3300
\
3200 ~
\
w
3100 ~
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u,
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c:(
3000 a:
o
2900 - a:
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c:(
2800 .84
2700
2600
2600
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2400
2300
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93
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86/
3500
92
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87/
3600
91
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84 86 86 87 88 89 90 91 92 93
C.G. LOCATION (INCHES AFT DATUM)
c.c. RANGE
AND WEIGHT
Figure 6-15
REPORT:
6-14
VB-1616
ISSUED: JULY 12, 1995
PA-44-180, SEMINOLE
SECTION 6
WEIGHT AND BALANCE
6.9 INSTRUCTIONS FOR USING THE WEIGHT AND BALANCE
PLOTTER
This plotter is provided to enable the pilot quickly and conveniently to:
(a) Determine the total weight and CiG. position.
(b) Decide how to change his load if his first loading is not within the
allowable envelope.
Heat can warp or ruin the plotter if it is left in the sunlight. Replacement
plotters may be purchased from Piper dealers and distributors.
When the airplane is delivered, the basic weight and basic C.G. will be
recorded on the computer. These should be changed any time the basic weight
or e.G. location is changed.
The plotter
graphically. The
The plotter does
than on the seats
enables the user to add weights and corresponding moments
effect of adding or disposing of useful load can easily be seen.
not cover the situation where cargo is loaded in locations other
or in the baggage compartments.
Brief instructions are given on the plotter itself. To use it, first plot a point
on the grid to locate the basic weight and C.G. location. This can be put on
more or less permanently because it will not change until the airplane is
modified. Next, position the zero weight end of anyone of the loading slots
over this point. Using a pencil, draw a line along the slot to the weight which
will be carried in that location. Then position the zero weight end of the next
slot over the end of this line and draw another line representing the weight
which will be located in this second position. When all the loads have been
drawn in this manner, the final end of the segmented line locates the total load
and the e.G. position of the airplane for takeoff. If this point is not within the
allowable envelope it will be necessary to remove fuel, baggage, or passengers
and/or to rearrange baggage and passengers to get the final point to fall within
the envelope.
Fuel burn-off and gear movement do not significantly affect the center of
gravity.
ISSUED: JULY 12, 1995
REPORT: VB-1616
6-15
SECTION 6
WEIGHT AND BALANCE
PA-44-180, SEMINOLE
SAMPLE PROBLEM
A sample problem (Figure 6-17) will demonstrate the use of the weight
and balance plotter.
Assume a basic weight and C.O. location of 2364 pounds at 86.14 inches
respectively. We wish to carry a pilot and 3 passengers. Two men weighing
180 and 200 pounds will occupy the front seats, and two children weighing 80
and 100 pounds will ride in the rear. Two suitcases weighing 25 pounds and 20
pounds respectively, will be carried in the rear compartment. We wish to carry
60 gallons of fuel. Will we be within the safe envelope?
(a) Place a dot on the plotter grid at 2364 pounds and 86.14 inches to
represent the basic airplane. (See illustration.)
(b) Slide the slotted plastic into position so that the dot is under the slot
for the forward seats, at zero weight.
(c) Draw a line up the slot to the 380 pound position ( 180 + 200) and put
a dot.
(d) Continue moving the plastic and plotting points to account for weight
in the rear seats (80 + 100), baggage compartment (45), and fuel
tanks (360).
(e) As can be seen from the illustration, the final dot shows the total
weight to be 3329 pounds with the CO. at 89.30. This is well within
the envelope.
(f) There will be room for more fuel.
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As fuel is burned off, the weight and CO. will follow down the fuel line
and stay within the envelope for landing.
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REPORT: VB-1616
6-16
ISSUED: JULY 12, 1995
SECTION 6
WEIGHT AND BALANCE
PA·44·180, SEMINOLE
MAX. T.O. AND
3800 LANDING
3700-----
WEIGHT-
89
90
91
92
93
A=--"""'T'-__,r---r-- .•..•
8~8~--_r--_+---~-+_-,
3600------~~-+_--~--_r--_+--~--_;
3500----~~--+_--+---4_--_r--_r--_+--~
3400-85
.~--+---+_--+_--+_--+_--+_--+___;
C/)
0:1
3300-~~--~--+---+---~I:I:
3200-~~---r---r--~--~--r-~~~---;
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3100-~+-·~~---+---r--~~~~--_+--;
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Iu,
3000..
~+--t---+----4---------1+-~I---+---t---f
c
2900-~+__r--+__4--~-+__4--_r--+__;
<t
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280084+--+--r--7f-
I
2700---+--~-H-~-r--r--+--+__+__;
r
~+-~FRONTSEATS--+--r~
I;:.
2500-~
':1
\--\--Hc--If--+--+--1~~-+~
2400-- ~ \--+--H~B-:-A-S..•.
IC~WL:cE::-:I~G-:-H::-::T:'--t---I
u.
2300----
AND C.G
84 85 86 87 88 89 90 91 9293
C.G. LOCATION (INCHES AFT DATUM)
SAMPLE PROBLEM
Figure 6-17
ISSUED: JULY 12, 1995
REPORT: VB·1616
6·17
SECTION 6
WEIGHT AND BALANCE
PA·44·180, SEMINOLE
THIS PAGE INTENTIONALLY LEFT BLANK
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REPORT: VB·1616
6·18
ISSUED: JULY 12, 1995