It is worth clarifying the definition of "alert" takeoff.
Aircraft on SIOP* nuclear alert---those that sat in the Christmas trees around which this thread is based---were configured at maximum gross weight including fuel, EWO gear, and (for bombers) nuclear weapons and defenses. There was no peacetime plan to launch a SIOP-configured aircraft as the takeoff was considered a high-risk proposition, especially if an engine was lost or at high temperature and pressure altitude. Under emergency conditions, a few SIOP KC
-135 tankers have been launched to provide fuel for an aircraft in distress, but only if there are no other tankers within the vicinity either airborne or capable of timely launch. A Blytheville AFB KC
-135A, for example, launched at maximum gross takeoff weight from SIOP alert to refuel an EC
-135 that was reverse refueling a KC
-135 with a landing gear problem, and the alert crew received the Air Medal for their flight, notably the takeoff.
"Strip alert" tankers were configured with high (not maximum) gross takeoff weights and were intended only to refuel non-SIOP aircraft under emergency conditions. They were often located at tanker task force bases (such as RAF Mildenhall or Eielson AFB) or in support of higher-headquarters directed missions (such as reconnaissance or fighter drags).
Because they were loaded with nuclear weapons, SIOP bombers did not launch from alert. During Operational Readiness Inspections (ORIs) or other evaluations, the weapons were removed and fuel loads reduced for planned launches from the alert facility. CHROME DOME and other missions which did carry nuclear weapons did not takeoff in EWO configuration (e.g., max gross weight) to reduce risk of accident involving the weapon.
|Quoting rfields5421 (Reply 9):|
On alert takeoffs, the plane is usually off the runway in 6,000-6,500 ft and begins to climb quickly.
This was not true under most SIOP/EWO alert conditions. SAC
runways were usually 8,000-10,000 feet long, and under most temperature and pressure altitude conditions the planned takeoff roll was often within 1,000 feet of (or very nearly equal to) critical field length, which meant that if a plane lost an engine after a certain point in the takeoff roll it could safely stop in the runway remaining. Under some EWO weather conditions, takeoff would be in the realm where after an engine loss the airplane could neither stop nor become airborne in the remaining runway (including the overrun) which meant a major accident. EWO alert takeoff rolls tended to be 8,000-9,000 feet.
Climbing was also a slow proposition. In the KC
-135 takeoff profiles (T/O Max mode) allowed for a very small height gain to clear airfield obstacles (say 300-500 feet above ground level) then the airplane would fly for a minute to several minutes in a relatively level attitude to accelerate to climb speed. Without this time to accelerate, the airplane could (especially if it lost an engine) enter a flight regime where it could neither climb nor accelerate.
* --- SIOP - Single Integrated Operations Plan, the name for the U.S.-led nuclear strike plan.
KC-135A, A(RT), D, E, E(RT), Q, R, EC-135A, C, G, L, RC-135S, U, V, W, X, TC-135S, W