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Alternate Minima and Fuel Policy

by K.Haroon: Last Updated on 23rd December 2006

Trip Fuel: Is the fuel required from departure station to planned destination based on forecast meteorological conditions. It includes fuel regarding:

• Take Off and Acceleration

• SID (or fuel for 6 nm if no SID is published)

• Climb

• Cruise

• Descent

• STAR

• Instrument Approach Procedure (6 min) to land

Additional (to TRIP) Fuel: Includes fuel regarding:

• APU

• Startup and Taxi

• Contingencies

• Alternate

• Holding

• Unusable quantities

Alternate Fuel: Is the fuel required to fly to an alternate airport, based on forecast meteorological conditions. It includes fuel regarding:

• One missed approach at destination (fuel for 6 nm is included to join the airway after missed approach)

• Climb

• Cruise (at LRC)

• Descent

• STAR

• Instrument Approach Procedure (6 mins) to Land

Holding Fuel: Is the fuel required for:

• 30 Minutes (may be 15 minutes, see details under Favorable Destination)

• Clean configuration

• At 1500 feet

• Over the Alternate Airfield

• In standard atmospheric conditions

• Calculated at estimated landing weight at the alternate airfield

Reserve Fuel: Is the sum of Alternate and Holding Fuel

Block Fuel: Is the sum of the following fuels:

• Taxi

• Trip

• Contingency

• Alternate

• Holding

• Stored

• Discretionary

Favorable Destination: As per ICAO Annex 8, Part I, Chapter 4, Clause 4.3.4.3 (a), no alternate aerodrome is required to be selected and specified in the Operational and ATC flight plans if the duration of flight and the meteorological conditions prevailing are such that there is a reasonable certainty that, at the estimated time of arrival at the aerodrome of intended landing, and for a reasonable period before and after such time, the approach and landing may be made under visual meteorological conditions.

PIA has adopted a conservative approach. Destinations requiring no alternate are termed as "Favorable Destinations". According to FOM chapter 3 clause 5.1.7. an airport is considered as a Favorable Destination when it satisfies all the following conditions:

a) It has more than one independent runway suitable for landing (runways that do not meet or intersect).

b) It has one prescribed instrument approach procedure for each runway.

c) It has a weather forecast for a period + 2 hrs of ETA indicating:

• Ceiling 2000 feet or more

• Visibility 5 Km or more

The clause specifies VMC conditions, reasonable period before and after ETA i.e. + 2 hours and in addition, will ensure landing even if one runway gets blocked or Wx deteriorates unexpectedly (though very unlikely). In addition to the above strict criteria, PIA policy is further conservative.

Clause 5.2.8 of FOM Chapter 3 requires Block Fuel to be higher of the following quantities:

A COMPANY POLICY	B ICAO REGULATION
Taxi Fuel	Taxi Fuel
Trip Fuel	Trip Fuel
Contingency Fuel	Contingency Fuel
Alternate Fuel	---
Holding fuel for 15 minutes at alternate	Holding fuel for 30 mins at destination

Whereas, criteria B is the one that is required by ICAO, criteria A is applicable on all PIA flights due to the requirement of alternate being atleast 100 track NM away. Thus, when dispatched to a "Favorable Destination". PIA flights will always carry fuel for alternate and atleast 15 minutes holding at alternate, the sum being more than 30 minutes holding fuel at destination.

For dispatch purposes, block fuel will be higher of requirements given under A and B as mentioned above. However, in case of excess fuel consumption, if crew estimates that 30 minutes holding fuel will be available as reserve at destination, continuation of flight to a "Favorable Destination" is perfectly legal as it meets all regulatory requirements.

Take-Off Alternate: Is the requirement of an alternate airport for take-off when weather conditions at airport of departure are below the landing minima for that airport. The distance of the alternate airport from the departure airport should not be more than:

• Distance equal to a flight time of one hour at the single engine cruise speed, incase of 2 engine aircraft.

• Distance equal to a flight time of two hour at one engine inoperative cruise speed, incase of 3 or 4 engine aircraft.

Alternate Airfield Selection:

• If destination forecast weather for a period of + 2 hrs of ETA indicates ...

  i. Ceiling 2000 feet or above
  ii. Visibility 5 Km or more

  - ONE nearest suitable alternate required.

  - FUEL should be carried for atleast 100 nm.

• If destination forecast weather + 1 hr of ETA is above its own Alternate Minima for an instrument approach ...

  - ONE alternate required.

  - DISTANCE of alternate should be more than 100 track nm.

• If the Weather Criteria is Not Met then:

  - TWO alternates required.

  - DISTANCE of one of the alternates should be more than 100 track nm.

  - FUEL to be carried for the alternate that is the furthest of the two.

Applicable Planning Minima:

• For Destination Airport: Approach minima as published on the Jeppesen Charts of the respective airport.

• For Alternate Airport: Alternate minima as published on the Jeppesen Charts of the respective airport. If alternate minima are not mentioned then:

  Type of Approach in Use	Applicable Planning Minima
  Precision Approach (CAT 1)	Non Precision Approach
  Non Precision Approach	Circling Approach
  Circling Approach	Cloud Base 2000 feet or higher Visibility 5 Km or more

• Once airborne the Jeppesen Approach Chart Minima shall be applicable.

In Flight Fuel Checks: At first convenient waypoint in cruise and thereafter every 45 minutes.

Minimum Fuel Procedure:

• Landing at Destination: Inform ATC if landing with less than Reserve Fuel.

• Landing at Alternate: Inform ATC about fuel remaining in minutes, if landing with less than Holding Fuel.

TEMPO: Condition in the forecast to be considered when weather is below minima at ETA.

PROB: Condition in the forecast to be considered if the probability factor is 30% or more.

Dispatch Requirements for Fuel:

• TAXI Fuel: 200 Kg (including APU consumption).

• Contingency Fuel: 5% of TRIP Fuel. Min 500 Kg and Max 700 Kg.

• Min Block Fuel: 4000 Kg

SOFTWARE for FUEL CALCULATIONS:

This software (as an excell file optimized for Galaxy Tab 10.1) helps in calculating the required fuel for a flight. It can be used in the cockpit for reducing the mathematical workload and errors. However please note that This is Not a Certified Software and I have developed it for my personal use and convenience.

Click Here to Download

Incase you encounter a problem in downloading. Right click on the above link and select "Save Target As"

Disclaimer: "B737-300 Fuel Policy and Planning Minima" are personal notes of the author. These notes do not sanction any pilot to violate his Company's Standard Operating Procedures, Aircraft Manuals or Manufacturer's Recommendations.