Minimum Interval Takeoff

Three United States Air Force Boeing B-52G Stratofortresses depart during a minimum interval takeoff exercise at Barksdale Air Force Base in 1986

A Minimum Interval Takeoff is a technique of the United States Air Force for scrambling all available bomber and tanker aircraft at twelve and fifteen second intervals, respectively.[1] Before takeoff, the aircraft perform an elephant walk to the runway. It is designed to maximize the number of aircraft launched in the least amount of time possible before the base faced a nuclear strike, which would obliterate all remaining aircraft.

Although the practice is aimed to efficiently send aircraft off as quickly as possible, it does not come without risks. Sending aircraft into the slipstream of another aircraft at such close intervals could cause the plane to jump up and down, possibly causing it to flip over. More than once, aircraft have crashed on takeoff after encountering such turbulence.

Description

Minimum Interval Takeoff was designed by the United States Air Force to get its bomber fleet in the air within fifteen minutes of an alert of an incoming missile attack, that being the time in which the bases would be obliterated.[1] Although it had roots during the Second World War, the tactic came of age during the Cold War.

Tactical use

Two C-130 Hercules aircraft of the 463rd Tactical Airlift Wing get airborne as the remaining 16 aircraft wait on the runway during a minimum interval takeoff at the start of a mass airdrop exercise at Dyess Air Force Base

Strategic Air Command bomber and tanker crews would frequently practice these drills, as they knew they had to send up the maximum number of planes, in the fastest time possible. This was done to prevent possible obliteration should the base be attacked by nuclear warheads. In theory, the whole procedure had to be done as soon as possible, as there would be minutes to spare in the event of an attack warning. This meant that the aircraft would be launched as quickly as 12 seconds between bombers, and 15 seconds between the tankers. Normally, aircraft are launched so that there is space between the turbulence of the aircraft ahead of it. Because of the small launch window, this made the air very rough for the next minute for the aircraft, during the takeoff roll and initial climbout. Water injection in the J57 produced extra power for takeoff but caused large amounts of unburned fuel to leave the engine in the exhaust, producing large amounts of black smoke which the subsequent aircraft would also have to go through in order to take off successfully. The J57 was fitted to all B-52’s, except the H-model.[2] During alerts, the men would perform an elephant walk from the Christmas tree, and then launch as quickly as possible. Typically, takeoff clearance would be received by the aircraft once the aircraft ahead of it was on the runway.

Upon taking off, the navigator would count down, with milestones having to be reached at important moments. If the aircraft wasn’t at speed during S1 time (120 knots, 140 mph), the plane would have to abort takeoff. At this point, the plane would pull up, becoming exposed to the violent turbulence which it immediately encountered. At 152 knots, the yoke would be pulled back, and the plane would begin to lift off.[3]

At Pease Air Force Base, it has been reported that B-47 Stratojet aircraft would launch at opposing sides of the runway at 7.5 second intervals, half that of a normal MITO.[4]

Incidents

A B-52H Stratofortress starts its engines during a Minimum Interval Takeoff on Barksdale Air Force Base in 2014

One B-52 was involved in a crash during a MITO when the aircraft stalled.[5]

On the morning of December 16, 1982, A B-52G Stratofortress of the 328th Bombardment Squadron, 93rd Bombardment Wing, at Castle Air Force Base crashed while attempting a MITO, killing all 9 crewmembers on board. It had just taken off from Mather Air Force Base when they encountered trouble. The aircraft, which was carrying 290,000 pounds of fuel, crashed about a mile and a half from Mather and blew up in a ball of fire around 250 feet in diameter. The resulting crash left a 400-yard path of burning debris, killed three horses, and left four people needing treatment for smoke inhalation.[6] The cause was determined to have been the result of the jet trying to avoid the jetwash of the lead plane, showing the inherent risk behind launching aircraft so close together.

A "Broken Arrow" incident originated from a minimum interval take off incident on December 8, 1964. During a normal MITO at Bunker Hill Air Force Base, Indiana, a B-58A Hustler, loaded with six nuclear weapons, suffered a landing gear failure. This caused the pilot to lose control, which also caused a rupture of the fuel cell holding JP-4 fuel, causing an immediate fire under the aircraft. The pilot and defensive systems operator survived the fire and abandoned the aircraft, the navigator ejected but was killed. The resulting fire consumed the aircraft and some nuclear weapons, causing contamination in the immediate vicinity.[7]

On 4 January 1961, during a minimum interval takeoff from Pease AFB, New Hampshire, Boeing B-47E Stratojet, 53-4244, of the 100th Bomb Wing, number 2 in a three-ship cell, lost control, crashed into trees, burned. Killed are aircraft commander, Capt. Thomas C. Weller, co-pilot 1st Lt. Ronald Chapo, navigator 1st Lt. J. A. Wether, and crew chief S/Sgt. Stephen J. Merva.[8]

Pop culture

There is a scene from the film A Gathering of Eagles during which a MITO is observed to occur from beside the runway at Beale Air Force Base. The scene involves Colonels James Caldwell (played by Rock Hudson) and Hollis Farr (played by Rod Taylor) standing a few thousand feet down the runway, and watching B-52 Stratofortresses take off at fifteen second intervals.

See also

References

  1. 1 2 Yenne, Bill (15 December 2012). B-52 Stratofortress The Story of the Buff from Drawing Board to the Skies over Afghanistan. Zenith Pr. p. 57. ISBN 0760343020.
  2. ↑ "MITO Takeoffs, Loring AFB, Maine 1984". All-hazards.com. Retrieved 9 August 2012.
  3. ↑ Jones, Tom (2006). Sky Walking : An Astronaut's Memoir (1st Smithsonian Books ed.). New York: Smithsonian Books/Collins. ISBN 978-0060851521.
  4. ↑ When the Wolf Rises Linebacker II, the Eleven Day War. Authorhouse. p. 280. ISBN 978-1468525373.
  5. ↑ Ficarrotta, ed. by J. Carl (2001). The Leader's Imperative : Ethics, Integrity, and Responsibility. West Lafayette, Ind.: Purdue Univ. Press. ISBN 978-1557531841.
  6. ↑ Beitler, Stuart. "Mather Air Force Base, CA B-52G Bomber Crash, Dec 1982". Retrieved 9 August 2012.
  7. ↑ Brewer, Randy (2012). "Broken Arrow Incident involving B-58A-CF 60-1116". B-58.com. Retrieved 9 August 2012.
  8. ↑ Lloyd, Alwyn T., "Boeing's B-47 Stratojet", Specialty Press, North Branch, Minnesota, 2005, ISBN 978-1-58007-071-3, page 160.
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