Both the C-141 Starlifter and C-5 Galaxy have T-tails, where the horizontal stabilizers and elevators are mounted on top of the vertical fin rather than on the sides of the aft fuselage. T-tails are usually only found on aircraft where the real estate on the sides of the aft fuselage is taken up by engines (Il-62, 727, DC-9, Tu-154, etc.), as the T-tail configuration has the serious disadvantages of
- needing a vertical stabilizer strong enough to carry the entire weight of the horizontal tail plus the considerable downward aerodynamic forces generated by same, making for a considerably heavier (and, thus, less fuel-efficient) airframe,
- causing maintenance difficulties, as it's harder for the mechanics to inspect and repair something that high up (this was an indirect cause of the crash of Alaska Airlines Flight 261), and
- being susceptible to an extremely dangerous "deep stall" condition, where, at an angle of attack slightly past the stall point, the disturbed wake from the aircraft's wings blanks out the horizontal tail, causing a total loss of pitch control and making recovery essentially impossible.
The C-141 and C-5 have conventional wing-mounted engines, yet both have the tail configuration of an aircraft with fuselage-mounted engines; why is this?