G-280 Fuel

Question 1

Usable Fuel Capacities

Volume / Weight

Answer 1

> Volume = 2179.1 gallons

> Weight = 14,620 pounds (6.7 lb./gal)

> Weight When Gravity Refueling =
9,760 pounds (6.7 lb./gal)

NOTE: Gravity refueling only fills the wing and feed tanks and can take a significantly longer time.

(AFM 1-28-10)

Question 2

Maximum Fuel Imbalance:

• On Ground
• In Flight

Answer 2

Takeoff = 450 pounds

In Flight, Approach and Landing = 900 pounds

The Fluid Quantity Management Computer (FQMC) will compare the fuel quantity between the two wings and provide a caution (amber) “Fuel Imbalance” CAS message if the difference between the wings is greater than 450 pounds on ground or 900 pounds in air.

(AFM page I-14)

Question 3

How is the aircraft normally refueled?

Answer 3

Through the single point connection located on the right front side fuselage.

(OM 2A-28-10 and 2A-28-30, 1 and 2A)

Question 4

Primary Fuel Types

Answer 4

> Jet A

> Jet A-1

> JP 8

> JP 5

Question 5

Is there an alternate method to fill tanks?
And,
Are there any limitations?

Answer 5

Yes, Fuel can be added through the over wing points. Fuel is only added to the wing tanks and feeder tanks.

(OM 2A-28-10 and 2A-28-30, 2A)

Question 6

Fuel Tank Temperature Limitations

Answer 6

Jet A fuel type:
> Minimum = -38 C
> Maximum = 57 C

Jet A-1 and JP 8 fuel types:
> Minimum = -46 C
> Maximum = 57 C

• Flight is prohibited when indicated fuel tank temperature is outside the minimum or maximum specified above.

(AFM 1-28-20)

Question 7

What are the methods for maintaining fuel balance?

Answer 7

1) XFLOW
2) INTERCONNECT

(OM 2A-28-10, 3rd paragraph, and 2A-28-30, 2C(4))

Question 8

What happens when the crossflow valve is opened?

Answer 8

X FLOW

> With the use of a boost pump you can transfer fuel from one feed tank to another. (Known as “Power Crossflow”).

> The Power Crossflow rate varies between 3500 pph and 4000 pph (depending on the operating conditions) or about 292 to 333 pounds every 5 minutes.

(OM 2A-28-30, 2C(4))

Question 9

What happens when the intertank valve is opened?

Answer 9

INTERCONNECT

> Fuel can gravity flow between the two wing tanks allowing the tanks to balance. (Known as “Gravity Crossflow”).

(OM 2A-28-30, 2C(4))

Question 10

What things occur when the jettison switch(s) is/are pressed?

Answer 10

JETTISON

1) The switch illuminates “FUEL JETT”,
2) The on side STBY PUMP will illuminate ON, and
3) The synoptic page will show the fuel path.

> The jettison flow rate will be between 5,000 to 7,000 pph per side, dependent on flight conditions.

(OM 2A-28-30, 2D)

Question 11

What will stop the jettison process?

Answer 11

MANUALLY:
> By pilot inputs by selecting the “FUEL JETT” (JETTISON) switch OFF.

AUTOMATICALLY:
> At 800 pounds of fuel remaining per side (on the respective side), allowing for a climb from sea level to 10,000 feet and thereafter allowing 45 minutes cruise.

(OM 2A-28-30, 2D)

Question 12

Fuel Storage System

Answer 12

7 Tanks
> Two (2) Integral Wing Tanks,
(Inner, Outer, and Vent Tank Compartments).
> One (1) Center Tank in the center wing area.
> One (1) Tank aft of the Center Tank.
> One (1) Tank forward of the Center Tank.
> Two (2) Feed Tanks, one dedicated to each engine and located in the aft portion of the Center Tank.
* Also, there are two (2) Vent Tanks, one on each wing tip. (Wing Tanks are divided into three (3) compartments: Inner Tank, Outer Tank, and Vent Tank).

(OM 2A-28-20, 1)

Question 13

Capacity of Each Tank

Pounds

Answer 13

Wing Tank (each):
4340 (OM); or 4350 (PTH and QRH)

Feed Tank (each):
530

Center Tank:
2140 (OM); or 2130 (PTH and QRH)

Forward Tank:
1610 (OM); or 1600 (PTH and QRH)

Aft Tank:
1130 (OM); or 1110 (PTH and QRH)

• Total Tank Capacity (pounds): 14,620

(PTH pages 4-4 to 4-6 and OM 2A-28-20)

Question 14

Water Drains

Answer 14

12 Total (some are part of the Fuel Dump Valves, which are used for gravity defunding). Dump/Drain Valves are located in the lowest point of the tank (or where water entrapment is possible).
> 7 Water Drains:
* One in Center Tank right of Rib 0,
* One in each Feed Tank,
* One in each Wing Tank outboard of Rib 2,
* One in each Vent Tank.

> 5 Fuel Dump Valves:

• One in FWD Tank,
• One in Center Tank outboard of Rib 0,
• One in each Feed Compartment,
• One in Aft Tank.

(OM 2A-28-20, 1)

Question 15

How is normal fuel feed to the engines, APU and the transfer of fuel between tanks accomplished?

Answer 15

> By ejectors (jet pumps), which are powered by motive flow provided by the high pressure section of each engine HMU (Hydro-Mechanical Unit / Engine Driven Fuel Pump).

> During engine starts, motive flow is locked out. To ensure adequate fuel pressure for the start, the Standby Fuel Pump is activated and the Fuel SOV must be opened. Once the engine reaches 39% N2, the motive flow lockout valve opens allowing motive flow to the jet pumps, supplying fuel to the engine. At this time the operator can set the Standby Pump to ARM (Normal) or OFF.

Question 16

Fuel Overflow Sequence

Answer 16

> The required depletion sequence is met using overflow pipes between the tanks. Overflow goes from the Feed Tank to the Wing Tank through a stack pipe. If the Wing Tank is full, it overflows to the Center Tank. If the Center Tank is full, it overflows to the AFT and finally to the FWD Tank. A flapper valve located at the pick up line prevents reverse flow when the tank is empty. (Opposite of the Depletion Sequence).

Overflow Sequence:
FEED-WING-CENTER-AFT-FWD

Depletion Sequence:
FWD-AFT-CENTER-WING-FEED

Question 17

Pressure Refueling Sequence

Sequence of Tanks

Answer 17

> Wing Tank Inboard / Feed Tanks

> Wing Tank Outboard

> Center Tank

> AFT Tank

> FWD Tank

Question 18

In what order will the fuel deplete if all tanks are full?

Depletion Sequence

Answer 18

(Opposite of the Overflow Sequence)
>  FWD Tank
>  AFT Tank
>  Center Tank
>  Wing Tanks
>  Feed Tanks

The feed lines on the Fuel Synoptic page will show amber between the tanks to indicate wrong transfer sequence. FWD should be empty when total fuel is less than 13,000 lb. AFT should be empty when total fuel is less than 12,000 lb. CTR should be empty when total fuel is less than 9,900 lb.

Question 19

How can fuel imbalances be corrected?

Answer 19

> By the power crossflow valve between the two feed tanks, or

> By the gravity crossflow valve between the two Wing Tanks.

(OM 2A-28-30, 2C(4))

Question 20

When will the two Standby Pumps operate?

Answer 20

> Automatically when fuel pressure drops below 4.5 psig, or

> When the crew activates them.

• Also, in the ARM mode the Standby Pump automatically stops when the pressure is 6.0 psig or greater.

(OM 2A-28-30, 2D)

Question 21

Methods of Refueling

Answer 21

1) Pressure (AUTO) Refueling
2) Manual (MAN) Refueling
3) Gravity Refueling

(OM 2A-38-30, 2A)

Question 22

What tanks can be fueled by Gravity Refueling?

Answer 22

The Wing Tanks and the Feed Tanks

> The Center Tank cannot be refueled by gravity due to the location of the overflow pipes in relation to the Gravity fill ports. The FWD and AFT tanks cannot be refueled by gravity due to the fact that the Center Tank cannot be gravity refueled, and the location of the overflow pipe between the AFT and FWD Tanks.

Question 23

Methods of Defueling

Answer 23

1) Suction Defueling
2) Gravity Defueling

(OM 2A-28-30, 2B)

Question 24

Can the airplane be fueled using the external Refuel/Defuel Panel (RDP) without turning on main aircraft power?

Answer 24

Yes

> The RDP is powered by the Right Hot Bus and only needs to have its power switched on at the panel (the red Master switch).

(OM 2A-28-40, 2C)

Question 25

Where is the temperature sensor (for fuel) located?

Answer 25

In the right wing.

OM 2A-28-30, 2E last paragraph

Question 26

Regarding the Fuel System, what does pulling the Fire Handle do?

Answer 26

It sends a signal of fire shutdown to the FADEC, the engine Fuel Shut-Off-Valve (SOV) to close, and the Engine Driven Hydraulic Pump (SOV) to close. They also arm the squibs for the fire bottles.

Question 27

Aircraft Max Zero Fuel Weight

Answer 27

28,200 Pounds

Question 28

Fuel Requirements for Flight in IFR Conditions

FAA Part 91

Answer 28

> Must carry enough fuel (considering weather reports and forecasts and weather conditions) to:

1) Complete flight to the first airport of intended landing;
2) Fly from that airport to the alternate airport (if one is required - “1-2-3” rule);
3) Fly after that for 45 minutes at normal cruising speed.

> “1-2-3” rule: (FAR 91.169) IFR Flight Plan must include an alternate airport unless the weather is at least 2,000 feet ceiling and 3 miles visibility, from 1 hour before to 1 hour after the ETA.

(14 CFR Part 91.167)