News

Aviation Explained: Do what you are TOLD

  • Published
  • By Greg L. Davis
  • 436th Airlift Wing Public Affairs
DOVER AIR FORCE BASE, Del. --  In the flying world, doing what you are told is a must for safe, efficient operations. Here, TOLD stands for take-off and landing data and is information derived from known facts about the aircrafts' performance and the main conditions that impact that performance.

TOLD is what pilots and aircrews use to determine if the aircraft will be able to take-off and land safely and then operate efficiently for the mission, or not at all, in some cases.

This data and how it is derived is so important it is taught to every person training to become any type of pilot as it affects all flying machines. The TOLD is based upon the aircraft weight, airfield altitude, the prevailing temperatures and other factors such as runway conditions.

Production aircraft have known performance capabilities which are determined by the manufacturer under standard, repeatable conditions. All certified aircraft are tested to determine exactly where the 'performance envelope' is by company pilots and/or test pilots. This information is all plotted out in a table or series of tables where variables can be dropped in and plotted. If the point falls within the specified safe limits of the graph, then the aircraft can do just that-operate safely; if outside of this 'performance envelope' then it is unsafe.

Air density has the largest influence on aircraft performance and where the point will fall on the graph. It is determined by four main factors: altitude, pressure, temperature and humidity. Without getting into formulas, the easiest way to understand this is to know that aircraft engines and wings are the most efficient when the air is cold, has low humidity and therefore has high density. They are least efficient when the air is hot, has high humidity and therefore has low density. It is all about how close the molecules of air are together.

Now let us look at the factors pilots look at when determining TOLD.

Weight: Total weight of the aircraft to include cargo, fuel and passengers.

Altitude: Pressure altitude at the airfield. Because air pressure varies based upon weather patterns it is important to use the most recent (accurate) data.

Temperature: Surface and wind temperatures affect the density of the air as described above.
Since most of us cannot control the weather, when the TOLD needs to be adjusted to fall within safe parameters, the weight of the aircraft must be changed. This usually means reducing the weight by carrying less fuel, passengers or cargo or a mixture of the three.

The Air Force operates a wide variety of aircraft. Here at Dover AFB, Delaware, the fleet of C-5M Super Galaxy and C-17A Globemaster III aircraft routinely operate out of some of the most challenging airfields in the world when it comes to TOLD.

Tech. Sgt. James Ellis, C-5M Formal Training Unit evaluator flight engineer, discusses the variables he uses to find the TOLD.

"Aircraft weight, atmospheric conditions based on pressure altitude, runway conditions such as rain, snow, slush," said Ellis. "You take all that into consideration and it's all graphed out."

Capt. Aaron Klang, FTU C-5M Super Galaxy instructor pilot, reinforces the importance of using TOLD properly.

"High, hot and heavy are our worst-case scenarios," said Klang. "We run into this a lot during mission execution. All of our downrange locations it's critical, that's where we are operating the heaviest and the elevation of the field is high."

Missions don't go without knowing exactly how the aircraft is going to perform for the prevailing conditions. Safe operations of Air Force aircraft require adherence to set standards. Doing what you are TOLD means the aircraft will be able to take-off and land safely.