Because of late delivery and protracted development of the F-111D, 94 F-111Es were ordered with simplified avionics and the TF30-P-3 turbofan engine, but with the Triple Plow 2 air intakes of the F-111D. They were ordered in 1968. Even though the F-111E had a later series letter than the F-111D, the E preceded the D into service.
As compared to earlier F-111 variable-geometry air intake configurations, the Triple Plow 2 air intakes were four inches farther from the airframe in order to improve boundary layer "plow", and the translating cowl was replaced by a series of three blow-in doors. These blow-in doors are a set of auxiliary inlets placed on the sides of the main intakes which enable extra airflow to reach the engine inlet ducts during takeoff or when the engines are at full power but the aircraft is moving slowly. They are normally sealed closed by spring-loaded doors which are pushed open by air pressure when additional airflow to the engines is needed.
The F-111E carried the APQ-113 forward-looking attack radar which is used by the navigator for navigation, air-to-ground ranging and weapons delivery. It can also be used in the air-to-air mode, although this is not the primary mission of the F-111E.
The first flight of an F-111E took place on August 20, 1969, and deliveries to the Air Force took place from 1969 to May 28, 1971. A total of 94 were built, and serials were 67-115/124 and 68-001/084.
TAC's 27th Tactical Fighter Wing at Cannon AFB reached initial operational capability with the F-111E in the fall of 1969. The wing had 29 F-111Es by December, but these flew under restrictions until the Air Force was convinced that the wing longerons were safe.
The F-111E program slipped another six months following the December 1969 loss of the 15th F-111A. The Air Force grounded the entire fleet and refused to accept the delivery of any more F-111s until the problems were fixed. All F-111Es went through the Recovery Program and other structural inspections that stemmed from the December 1969 accident. The order that grounded the fleet was finally lifted in July of 1970.
The F-111E had integral radar homing and warning equipment and possessed electronic countermeasures capability. This made the aircraft needed in Europe right away. Despite the program's slippage, the first two of the 70 F-111Es slated for the 20th Tactical Fighter Wing in Europe were sent to the RAF Upper Heyford base in Oxfordshire, England on September 11, 1970. The wing became fully operational with the type in November of 1971. These F-111Es remained based at Upper Heyford up to 1993, when defense cutbacks and the overall decline in the threat from the East resulted in their withdrawal to stateside bases.
F-111Es of the 20th TFW were used in Operation *Desert Storm* in early 1991, flying out of bases at Incirlik, Turkey. They lacked the precision guided munitions capability of the later F-111F, and so they carried mainly Mk 82 or Mk 84 standard conventional bombs and other conventional ordnance against targets in the northern part of Iraq. None were lost in combat, which is a remarkable testament to the efficacy of the F-111E in combat.
The first prototype of the F-111E series (67-0115) was loaned to NASA for tests in support of the Integrated Propulsion Control System. This was a "fly-by-wire" system installed in the weapons bay which automatically controlled the variable-geometry inlet and the turbofans. The first IPCS flight was carried out on September 4, 1975. The last flight was on February 27, 1976. After the tests were completed, the F-111E was returned to the Air Force and restored to its original configuration. It later served as a chase plane for the Rockwell B-1 strategic bomber.
Surviving F-111Es were all transferred to AMARC in 1993/94. A few are on display in museums.