Introduction
TOLD is an integral part of flying airplanes and it is calculated every flight. As we get briefed with the day's weather, one of the pilots will fill in the temperature and pressure altitude blocks of the TOLD card, or Take-Off and Landing Data card. This card is clipped to the center windshield post, and is used to set our takeoff and landing speeds based on our weight, outside temperature, and the pressure altitude of a given location. Pressure altitude is simply the altitude of a location above sea level. Maxwell AFB is about 200 feet above sea level, so it's usual to see a Pressure Altitude (PA) of about 0-300 feet. But at Colorado Springs, CO, the PA can be around 6,000-6,500 feet. The hotter and thinner the air, the less performance the jet can give us. The cooler and denser the air, the better it performs. So to plan for the conditions, we complete a TOLD card, which tells us exactly what kind of performance we can expect, and how fast or slow we need to fly on landing and takeoff.
Take-Off
Here is an example of a TOLD card. To explain, we'll start with the takeoff portion, on the left side. At the top of the card, the crews usually denote the climb gradient (listed as 3.3%...equal to 200 feet per nautical mile) and the call sign (listed as J072, or Josa 072). The station is the takeoff airfield, here listed as "LBL", or Liberal, Kansas. The temp is the current temperature. The P.A. is the pressure altitude of the field. The wind is the current wind measurement, listed in azimuth and knots. This one reads "180/23G31". This means the wind is coming from 180 degrees (due south) at 23 knots gusting to 31 knots. Next to the "Takeoff" block is the runway heading, and the active runway is circled. The one circled is runway 17, which is pointing at 170 degrees (south southeast). This means the wind is 10 degrees from the runway heading. Using this information, you can calculate a headwind component and a crosswind component. The crosswind is 5 knots, and the headwind is 22 knots. This is important to know because each aircraft has a maximum crosswind limit. Next is the RCR, or Runway Condition Report. This is used in determining other information, such as takeoff distance and V1 speeds, as wet or icy runways will require greater distances.
Next line is the T.O. WT. This is the takeoff weight, and there is a takeoff weight limit. Normally, under most conditions, the Learjet can always takeoff at it's maximum takeoff weight of 18,300 (denoted as 18.3 on the card). But at high elevations under hot conditions, it may only be able to takeoff with lower weights. Next to the takeoff weight limit is the actual takeoff weight, here listed as 15.3, or 15,300 lbs. This is determined by using the empty weight (10,700 lbs) plus the fuel and passengers.
The next line is the T.O. DIST., or takeoff distance. Here it's listed as 6,800 lbs. It's normally not this high (around 4,500 feet), but because the pressure altitude is at 4,000 feet and the temperature is 93, the airplane is sluggish and takes more runway distance to accelerate to takeoff speeds. Next to it is the runway available.
Below the distances is the meat of the takeoff section...the takeoff speeds. V1 is the Go/No-Go speed. If a problem develops below V1, the crew can abort. If it happens after V1, the crew must continue the takeoff. A successful abort cannot be accomplished at that point. Next is VR, or rotation speed. This is the speed at which the crew will rotate, or lift the nose of the airplane into the air. V2 is the takeoff safety speed, or the minimum speed the aircraft should be flown with one engine inoperative. VFS is the Flap Retract Speed, at which it is safe to retract the flaps (they are set at 8 degrees for takeoff on a Learjet).
VREF is the approach reference speed, or the full-flaps approach speed. Here, it is calculated for the takeoff weight, even if it is above the maximum landing weight of 15,300 lbs. In an emergency, we may not have enough time to dump fuel to reach the maximum landing weight. Next to it is the climb gradient for an Approach Climb profile, or a climbout with the airplane configured for landing. On this TOLD card, it's listed as 2.5%, which is analagous to 152 feet per nautical mile.
In the center-left of the Takeoff section is the N1 power setting for takeoff. N1 is the term used to describe the fan speed on the engine. Although the engine can max out at 103%, various PA and temperature combinations can limit this to avoid "overboosting" the engine, that is creating higher than normal pressure ratios in the engine, which can lower the engine life. In this case, 93.1% is the maximum recommended engine speed for takeoff. This does not mean that the pilots can't use more than that, but using more power every time will increase the wear on the engine noticeably.
Landing
Not too much different from the takeoff side, the landing side provides much of the same information. The temperature, PA, wind, crosswind, headwind and RCR blocks remain the same. The LNDG WT block is the maximum landing weight. Normally this is 15,300 lbs (15.3), but under certain conditions, the brakes may be limited, and the weight could be lower. The actual landing weight is calculated by subtracting the fuel weight burned enroute. The LNDG DIST is the landing distance, corrected for RCR, that the aircraft will require, in feet. NOTE: The landing distance takes into factor normal brake application, no greater than 10 knots fast on approach, with full flaps and spoilers extended, but does not take into factor using thrust reversers. This is a good thing, since the ACTUAL landing distance will likely be shorter with use of the thrust reversers.
VREF is the same as it was in the takeoff block. It is the minimum approach speed for full flaps (40 degrees). Other flap settings require higher speeds. Flaps 20 will require the pilots to fly VREF +10 knots on final. Flaps 8 degrees will require a speed of VREF + 20, and a flaps up approach will require VREF + 30. The Approach climb speed is the speed at which the pilot must climb to achieve the best climb gradient on a single engine. It is normally 7 knots above VREF.
Again, there is a block for takeoff power settings for the fan speed (N1), but instead of using it for takeoff, it is calculated for use in the event the crew must abort an approach and go around.
Summary
TOLD is an important exercise. On a typical day at a typical airfield, the airplane will have plenty of performance available, and TOLD is merely a formality. But at airports with hot temperatures and/or high pressure altitudes, and even at airports with normal conditions but require a non-standard climb gradient, TOLD becomes very important, and can mean the difference between being able to "make it" and "not make it". It takes the guessing out of the game, and allows pilots to make better decisions regarding their aircraft performance capabilities.
Behind the Scenes Index
Controller/Pilot Interface
Enroute Navigation...Getting There
Arriving and Departing an Airport