The autopilot manufacturer may not have considered the tip tanks
when developing the product or obtaining an STC for its installation.
One night in a Learjet, it manifested as eerie purple fingers stretching forward many yards into the night from the nose of the airplane and tip tanks
. Never did it adversely affect the radios, although after we landed the Lear, the captain showed me where the paint had been removed from the very front of the nose and tip tanks
and said, "St.
This particular aircraft was different--it had tip tanks
and an additional, separate fuel selector valve.
The original noncanted and bladder-equipped tip tanks
also had a fuel-pickup problem; an airworthiness directive mandated a hefty increase in unusable fuel.
For example in the airplanes I commonly fly, tip tanks
in Beechcraft Bonanzas and in-wing auxiliary fuel tanks in early Bonanzas and Barons are known for this fuel system characteristic.
I added two 15-gallon tip tanks
for range and comfort because the aircraft's tendency to fishtail in turbulence is somewhat diminished thanks to the good-looking canted tanks.
It doesn't allow the autopilot to be installed if the airplane has aftermarket tip tanks
installed under a separate STC.
Aftermarket mods such as turbonormalizing and tip tanks
can turn a 36-series Bonanza into an airplane that can carry four people 1000 NM at 200 knots.
Additionally, an STC may impose changes in the airplane's operating limitations, like removing a Bonanza from its Utility category certification and placing it in the Normal category, mandating a certain amount of fuel be in the tip tanks
for operations above the airplane's original MGTW, lowering the speed for turbulence penetration, VA, or some combination.
For years D'Shannon has specialized in mods for Beech Bonanzas, notably tip tanks
. It currently offers a 20-gallon tip tank--all usable--made of composite material.
Diamond Aire (www.diarnondaire.com) performs the Geronimo mod, and offers a number of other mods for the Apache-Aztec line including redesigned noses, dorsal fins, a speed-slope windshield, gap seals, vortex generators, tip tanks
and inflatable door seals.
Some aircraft with outboard tip tanks
are very sensitive to filling sequence.