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the 200 in the Midwest – we were about to depart from an elevation of 800 feet, at 11,500 pounds, with an OAT of 20°C and about an 8-knot headwind component. However, the crew – years before in the comfort of their hangar office – had worked out a lot of takeoff performance problems for their own home-base airport as well as other airports they frequently used. In all cases, they did the exercise based on worse-than-expected conditions. In this home-base case, they used 1,000 feet elevation, 45°C temperature, 12,500 pounds, no wind, no flaps. They found that both Accelerate-Stop and Accelerate-Go distances were less than the 8,000-foot runway they would be using.
If the airplane can perform satisfactorily using these worse-than-actual conditions, then is it not correct to believe that the actual performance will be better than (and certainly no worse than!) the performance numbers the POH provides even if we use the higher V-speeds for the higher weight? After all, we will reach those speeds in less time and our climb rate, using the higher V2, will be greater than the chart presents since we are at a lighter weight. As a side benefit, our margin above VMCA and VS will be greater than what the chart assumes, again due to our lighter weight. In effect, our margin for error is improved when “big numbers” are used. Even if we over-rotate and fall a bit below the “big number” V2, we may still be at or above the actual V2 for our real conditions.
The only detriment that comes with using the higher speed appropriate for a greater weight is increased tire wear, since we will be rolling on the runway to a higher speed. Personally, I am very willing to accept the slight extra maintenance cost, thinking the safety benefit it provides makes the cost worth it.
Awhile back, I was involved in transitioning a Phoenix- based flight department from their B200 into their newly purchased 350. The 350 had been extensively upgraded by Stevens Aerospace and Defense Systems (formerly Stevens Aviation) in Nashville as part of the purchase. The upgrades included the Blackhawk XP67A engine swap and installing the Garmin G1000NXi package ... making a great airplane even greater!
Being based at Cutter Aviation on the south side of Phoenix’s Sky Harbor Airport, the runway we were usually assigned was 7R – 25L, 7,800 feet long. Using the POH, as modified by the Blackhawk STC, I worked a takeoff performance problem using 2,000 feet Pressure Altitude (field elevation is 1,135 feet), 45°C OAT, 15,000 pounds takeoff weight (the maximum limit), Approach Flaps and no wind. Takeoff Field Length came out to be 5,672 feet, more than 2,100 feet less than what we had available. The “big numbers” associated with these conditions were 104, 105 and 109 KIAS for V1, VR and V2. My suggestion was to use these numbers for all of our KPHX takeoffs giving us a safety cushion, since rarely
FEBRUARY 2024
KING AIR MAGAZINE • 29