The Boeing F-15E dual-role fighter is an advanced long-range interdiction fighter and tactical aircraft. The F-15E is the latest version of the Eagle, a Mach 2.5-class twin-engine fighter. More than 1,500 F-15s are in service worldwide with the US Air Force, US Air National Guard and the air forces of Israel, Japan and Saudi Arabia, including over 220 F-15E fighters.
F-15 Strike Eagle programme and development
The F-15E made its first flight in 1986. It is armed with air-to-air missiles that can be launched from beyond visual range, and has air-to-ground capability to penetrate hostile air and ground defences to deliver up to 24,000lb of precision ordnance. Since 2001, US Air Force F-15E aircraft have been almost exclusively used for close-air support.
In April 2001, Boeing received a contract for a further ten F-15E aircraft for the USAF, bringing the total to 227. The air force initially planned to purchase 392 F-15s. The first production model of the F-15E was delivered to the 405th Tactical Training Wing, Luke Air Force Base, Arizona, in April 1988. The ‘Strike Eagle’, as it was dubbed, received initial operational capability on 30 September 1989.
Boeing is upgrading the programmable armament control set and software for the delivery of precision weapons like the joint direct attack munition (JDAM), joint stand-off weapon (JSOW) and the wind-corrected munition dispenser (WCMD).
Joint direct attack munition (JDAM)
Joint direct attack munition (JDAM) @boeing.com
Joint stand-off weapon (JSOW)
Joint stand-off weapon (JSOW)
Wind-corrected munition dispenser (WCMD)
Wind-corrected munition dispenser (WCMD)
The aircraft also have improved night vision capability and three new active-matrix liquid crystal displays.
In December 2005, the Government of Singapore placed an order for 12 F-15SG aircraft. Deliveries are scheduled for mid-2009 to 2012. In October 2007, Singapore ordered an additional 12 aircraft. The first F-15SG was rolled out in November 2008. Deliveries of F-15SGs are to begin in second quarter 2009 and continue till 2012.
In August 2008, the F-15E became the first fighter to fly powered by a blend of synthetic fuel and JP-8. The USAF intends to certify its entire fleet of aircraft for flight using the blended fuel by 2011.
F-15SE Silent Eagle stealth variant
F-15 Silent Eagle (F-15SE) @vignette1.wikia.nocookie.net
F-15SE Silent Eagle is an upgraded version of the F-15 Strike Eagle aircraft, being developed by Boeing for international customers. The F-15SE features an innovative design which reduces its radar cross section. A prototype of the F-15SE Silent Eagle aircraft was first unveiled in March 2009. The F-15SE flight demonstrator aircraft, F-15E1, completed its maiden flight in July 2010.
F-15SE is 63.6ft (19.4m) long, 18.5ft (5.6m) high and has a wingspan of 42.8ft (13m). The basic design of the F-15SE is similar to that of the F-15 Strike Eagle aircraft with new components added. The new components include the conformal weapons bay (CWB) instead of the standard conformal fuel tanks.
The CWB significantly increases the internal carriage capacity of the aircraft and also reduces its radar signature. Two additional weapons stations have been included to enable the aircraft to carry an additional four air-to-air missiles.
The Silent Eagle also features twin vertical tails canted 15° outward. Canted tails provide rear lift to the aircraft and reduce ballast usage, while increasing the range by 75 to 100 nautical miles. Coatings will also be applied to various areas of the aircraft to minimise the radar signature.
The F-15SE has also been designed to function as a non-stealthy, multirole aircraft. The CWBs can be removed and the aircraft can be reconfigured to include conformal fuel tanks based on mission requirements. Source airforce-technology.com
F-15 Silent Eagle cockpit artist impression
In March 2009, Boeing unveiled the F-15 Silent Eagle (F-15SE) at St Louis, Missouri, USA.
“The F-15 Silent Eagle is designed to meet our international customers’ anticipated need for cost-effective stealth technologies, as well as for large and diverse weapons payloads,” said Boeing F-15 programme vice president, Mark Bass.
Using a modular design approach, the F-15SE possesses aerodynamic, avionic, and stealth features. Key elements of the F-15SE include aerodynamic improvements, RCS reductions, an internal weapons bay and advanced avionics enhancements.
Aerodynamic changes to the F-15SE will improve the aircraft’s aerodynamic efficiency and fighter performance by reducing overall airframe weight and drag. The RCS reduction methods are applied to the airframe for frontal aspect stealth capability thus improving mission effectiveness.
The modular internal weapons bay contributes to the overall aircraft RCS reduction package while maintaining strike capability. The enhanced avionics include an integrated active electronically scanned array (AESA) radar and digital electronic warfare system (DEWS) that provides the pilot with greater situational awareness.
F-15 Silent Eagle (F-15SE) @dindebat.dk
The internal carriage conformal fuel tanks (CFTs) can be quickly replaced by the large payload external carriage CFTs which are optimised for increased weapons load. The innovative Silent Eagle is a balanced, affordable design solution based on the combat-proven F-15 Eagle.
The new sophisticated F-15SE internal carriage capability minimises aircraft radar signature and significantly increases pilot tactical options. It is equipped with two internal bays designed for multiple carriage configurations.
The F-15 Silent Eagle’s (F-15 SE) Basic Sensor Suit (Source: Pakistan Defense)
The F-15SE is capable of carrying electronic warfare, reconnaissance equipment, side-looking radar, and jamming equipment. The fighter plane’s reconfigurable capability provides enhanced combat flexibility. It is adaptable with each application reconfigurable every 30 minutes.
The elite F-15SE signature reduction methods are applied to the airframe for frontal aspect stealth capability, which ensure greater survivability in the battlefield. The F-15 family has a combat record of 101 victories and zero losses. The US Air Force’s F-15E has flown thousands of combat missions during worldwide combat operations.
F-15SE Silent Eagle: Details
F-15K Slam Eagle next-generation South Korean fighter
In April 2002, the Republic of Korea chose the F-15K as its next-generation fighter. 40 aircraft, to be known as the ‘Slam Eagle’, have been ordered. The first flight of the F-15K took place in March 2005 and deliveries began in October 2005. The F-15K entered operational service in July 2008 and deliveries concluded in October 2008. It was confirmed in April 2008 that 21 more would be ordered in 2010, the quantity includes an additional aircraft to replace one which crashed in 2006.
The South Korean Air Force received the last shipment of new F-15K fighter in October 2008 completing its decade-long project to procure 40 of the highly manoeuvrable aircraft. US aircraft manufacturer Boeing delivered F-15ks to the South Korea’s 11th Fighter Wing in Daegu.
The F-15K is powered by General Electric F110-GE-129 engines and features a new electronic warfare suite including BAE Systems IEWS ALR-56C(V)1 radar warner, BAE Systems IDS ALE-47 countermeasures dispenser system and Northrop Grumman ALQ-135M radar jammer.
Lockheed Martin will provide the Tiger Eyes sensor suite with targeting pod (mid-wave staring array FLIR, laser and CCD TV), navigation pod (terrain following radar and mid-wave staring array FLIR) and long-range IRST (infrared search and track). Raytheon will supply the AN/APG-63(V)1 multi-mode radar. BAE Systems will provide the AN/APX-113 IFF (identification friend or foe) system. Data Link Solutions will supply the MIDS fighter datalink.
Kaiser Electronics will provide the cockpit display suite including: five flat panel colour displays (FPCD), four 6in multi-purpose displays (MPD) and wide field of view head-up display (HUD). The FCPD and MFD feature active matrix liquid crystal display (AMLCD) technology.
ROKAF F-15, @Boeing
The Republic of Korea has ordered Raytheon AIM-120 AMRAAM and AIM-9X Sidewinder air-to-air missiles and Boeing SLAM-ER stand-off land attack missiles for the new aircraft. First flight of a SLAM-ER, which has a range of 278km (150nm), onboard an F-15E took place in February 2004. In 2010, the Republic of Korea Air Force also plans to procure AGM-158 joint air-to-surface stand-off missiles (JASSM).
See details of F-15K: HERE
While F-15A/C aircraft are single-crew aircraft, F-15B/D/E have a crew of two. The F-15E is crewed by the pilot and the weapon systems officer (WSO).
The WSO is equipped with two Sperry full-color and two Kaiser single-color cathode ray tubes. The WSO can access information from the radar, electronic warfare or infrared sensors, and monitor aircraft or weapons status and possible threats. The WSO also selects targets and navigates with the aid of a moving map display, produced by an AlliedSignal remote film strip reader.
Pilot @danwintersphoto.com WSO @eaglet.skr.jp
Main Instrument Panel
Short descriptions of the numbered controls displayed above:
(1) Mirrors – Three canopy frame mounted rear view mirrors (left, middle, right) which help increase pilot’s SA by being able to monitor part of the airspace behind the aircraft.
(2) Lock/Shoot Lights – Two orange lights built into the canopy frame which flash rapidly when a missile lock is achieved (in A/A mode). The rapid orange flashing is designed to quickly get the pilot’s attention.
(3) Air Refueling Ready Light – Illuminates when the aircraft is ready for refueling boom engagement (after the air refueling process has been initiated by the pilot).
(4) Chart Light – A small directional light to help reading the map strapped on the thigh of the pilot.
(5) Head-Up Display – The HUD is used to project tons of information right into the pilot’s forward vision. For more details see: Head-Up Display.
(6) Standby Magnetic Compass – Although an electronic compass strip is constantly displayed on top of the HUD, the Strike Eagle uses a completely conventional magnetic compass built into the canopy frame.
(7) Up-Front Control – The UFC is a control panel which houses a lot of functions with its 6 lines of alphanumeric displays and 12 pushbuttons on both ends of the lines.
(8) Warning Lights – Red lights that are designed to get the immediate attention of the pilot: they are placed in almost eye level and if turned on, they shine with a bright red color.
(9) Multipurpose Displays – Three large LCD displays are used to present tons of information to the pilot. The middle display is in color ( MPCD) while the other two are green monochrome ( MPD’s).
(10) Cautions Lights – A couple of caution light placed in a relatively easy-to-notice corner of the dashboard.
(11) Hydraulic Pressure Indicators – Conventional gauges to display pressures of critical hydraulic systems.
(12) Clock – A conventional analog clock.
(13) Data Transfer Module Receptacle – The DTM is used to enter pre-designed mission information to the aircraft’s onboard computers. The DTM cartridge is prepared on mission planning computers during the mission planning phase and should be inserted into this receptacle before the mission.
(14) Cockpit Pressure Altimeter – A traditional gauge showing cockpit pressure on an altitude scale between 0 and 50,000 feet.
(15) Engine Monitor Display – A digital display to present information about the engines of the aircraft. For more details see: Engines.
(16) Fuel Quantity Indicator – A combined indicator to display different fuel quantities. For more details see: Fuel Quantities.
(17) Caution Lights Panel – A set of caution lights each responsible for one specific system. They illuminate to indicate the occurence of a caution condition.
(18) Emergency Vent Handle – When turned 45° CCW, electrically dumps cabin pressure. Extension of the handle shuts off ECS air to the cockpit and allows ram air to enter the cockpit (the amount is controlled by how far the handle is extended).
(19) Holding Brake Switch – A switch to engage the holding brake.
(20) Jet Fuel Starter Control – A control handle to start the JFS. For more details see: Jet Fuel Starter.
(21) Multipurpose Color Display – Three large LCD displays are used to present tons of information to the pilot. The middle display is in color ( MPCD) while the other two are green monochrome ( MPD’s)
(22) Rudder Pedal Adjust Knob – A knob used to adjust the rudder pedals to the pilot’s personal preferences. The knob should be pulled out to adjust the rudder pedals (pushing feet against a spring pressure) and pushed back in to fix them in their adjusted position.
(23) Circuit Breaker Panel – Just what its name says, a panel containing an array of circuit breakers within easy reach of the pilot.
(24) Cockpit Cooling & Pressurization Outlet – An outlet for cockpit air exchange and cooling/heating.
(25) Energency Stores Jettison Switch – A switch used to quickly jettison ordnance and/or external fuel tanks.
(26) Vertical Speed Indicator – A conventional gauge to indicate vertical speed. Since vertical speed is displayed on the HUD, this instrument serves as a backup.
(27) Angle-of-Attack Indicator – A conventional gauge to indicate AoA. Since AoA is displayed on the HUD, this instrument serves as a backup.
(28) Emergency Break/Steering – A handle to be pulled out for emergency breaking/steering.
(29) Pitch Ratio Indicator – A conventional gauge to show the ratio of symmetrical stabilator motion to longitudinal stick motion (value between 1 and 0, the bigger the value, the bigger the stabilator motion for a given stick motion). Naturally, the higher the aircraft speed is, the lower ratio value is needed to pitch the aircraft.
(30) Pitch Ratio Select Switch – A two-way switch. When AUTO, normal pitch control functions are maintained. When EMERG, hydraulic pressure is removed from the hydromechanical pitch control system, which results the pitch ratio to move to a mid-range value (between 0.3 and 0.5) and lock there.
(31) Landing Gear Handle/Indicator Panel – A panel to operate landing gear and to display its status.
(32) Radio Call Panel – A panel to indicate radio calls.
(33) Emergency Landing Gear Handle – A handle used to emergency-rolower the landing gear (the gear doors open and the gear lowers by forces of gravity and drag).
(34) Arresting Hook Control Switch – A switch used to lower/raise the tail hook designed to catch the runway arresting cable in case of emergency.
(35) Canopy Jettison Handle – A handle used to emergency-jettison the canopy. Canopy is blown off by pyrotechnic charges.
(36) Armament Control Panel – A panel used to manipulate different armament settings.
(37) Standby Airspeed Indicator – A conventional gauge to indicate airspeed. Since airspeed is displayed on the HUD, this instrument serves as a backup.
(38) Standby Attitude Indicator – A conventional gauge to indicate aircraft attitude (also called as artificial horizon). It’s a completely mechanical backup indicator.
(39) Standby Altimeter – A conventional gauge to indicate altitude. Since altitude is displayed on the HUD, this instrument serves as a backup.
(40) Fire Warning/Extinguishing Panel – A panel used to display and/or extinguish engine fire. For more details see: Fire Warning System.
(41) Caution Indicator (EMIS) – An orange light which illuminates if the aircraft emits detectable electromagnetic energy (i.e. radar is emitting).
(42) Master Caution Switch/Indicator – An indicator to display and acknowledge a new caution status.
The pilot’s crew station features one full-colour and two single-colour cathode ray tubes. These are being upgraded to Rockwell Collins 5in Flat Panel Colour Displays using active matrix liquid crystal display (AMLCD) technology. A holographic wide-field-of-view head-up display (HUD) from Kaiser provides the pilot with flight and tactical information.
Kaiser HUD @f-15e.info
The F-15E HUD (Kaiser IR-2394/A) is much greater than the HUD in previous F-15 models (A, B, C, D), thus letting the system display more information. It provides a 21° x 28° field of view. Note that although the HUD glass is more or less rectangular, the limits of the maximal projected area are rounded (see photo above left), thus no image can be projected to the very edges of the HUD. Symbology projected to the HUD appear in green, its appearance can be controlled by the pilot, using the HUD controls under the UFC (Up-Front Controller). HUD symbology is projected as if ‘focused at infinity’, thus letting the pilot see the symbology sharply while actually looking at objects far in front of the aircraft. Source f-15e.info
The HUD control rack is located inthe middle of the pilot’s dashboard, right below the UFC. The rack contains all the control switches and knobs necessary for managing the appearance of the HUD symbology. Note that this rack houses the master mode selector buttons as well, which too have effect on the informaton displayed on the HUD. The following picture illustrates the layout of the HUD control switches and knobs and their functions are exlained in detail below.
Brightness Knob controls the brightness of the stroke symbology. Note that due to its nature, stroke symbology is always displayed at a ‘maximum contrast setting’.
Symbol Declutter Switch serves as a declutter switch for the HUD. When set to ‘NORM’, all stroke symbology appears on the HUD. When set to ‘REJ1’ or ‘REJ2’ some or all of the stroke symbology is removed from the HUD. Note that the pilot can program which symbology should be removed and which should remain in any of these settings. Brightness Knob #1 and Symbol Declutter Switch together are labeled as ‘SYM’, since they control the appearance of stroke symbology on the HUD.
Day/Night/Auto Switch sets the HUD display mode. When set to ‘DAY’, HUD symbology illumination goes to max power so information displayed on the HUD should be visible even in bright daylight. When set to ‘NIGHT’, symbology illumination is low, but still clearly visible against the dark sky. When set to ‘AUTO’, symbology illumination varies depending on ambient lighting. Note that oddly enough, in ‘AUTO’ mode, the HUD does not provide enough illumination in the dark.
Video Brightness Knob controls the brightness of the raster (video) symbology.
Contrast Knob controls the contrast of the raster symbology. Video Brightness Knob and Contrast Knob together are labeled as ‘VID’, since they control the appearance of video imagery on the HUD.
HUD (Kaiser IR-2394/A)
|– Available Gs
– Current Gs
– Mach Ratio
– True Airspeed
– Angle of Attack (AOA)
– Indicated Airspeed
– Pitch Ladder
– Command Heading Marker
– Heading Scale
|– Gun Cross
– Waterline Symbol
– Velocity Vector
– Barometric Altitude
– Radar Altitude
– Horizon Line
– Steering Data Block
– Ghost Velocity Vector
– Maximum Projected Area
F-15 ACES II
The F-15 Eagle is equipped with this version of the ACES II. It replaced an Escapac seat used in the prototypes and early aircraft. This version differs from the rest of the basic side-pull ACES II seats (A-10, F-117) in the configuration of the headrest canopy breakers, and the side-pull handles. The picture below shows the size difference between the handles on the A-10 (right) and the F-15 (left). The A-10 seats originally had no canopy breakers as in the example shown, but were later fit with a single canopy breaker. The F-117 has a metal canopy frame which precludes the use of a canopy breaker. The handles on the F-117 closely resemble the A-10 handles. Source ejectionsite.com
F-15 Eagle Losses & Ejections: Here
Joint helmet-mounted cueing system (JHMCS)
USAF F-15 pilot wth joint helmet-mounted cueing system (JHMCS)
USAF F-15s are scheduled to receive the joint helmet-mounted cueing system (JHMCS) developed by Vision Systems International. A contract for 145 systems was placed in July 2008. Deliveries are underway and are scheduled to conclude in mid-2009.
The F-15E aircraft can carry payloads up to 23,000lb. The aircraft can carry up to four Lockheed Martin / Raytheon AIM-9LM infrared-guided Sidewinder air-to-air missiles, up to four Raytheon AIM-7F/M radar-guided Sparrow air-to-air missiles, or eight Raytheon AMRAAM radar-guided, medium-range air-to-air missiles.
AIM-9LM infrared-guided Sidewinder
AIM-9L/M Sidewinder air-to-air missiles
The AIM-9L added a more powerful solid-propellant rocket motor as well as tracking maneuvering ability. Improvements in heat sensor and control systems have provided the AIM-9L missile with an all-aspect attack capability and improved guidance characteristics. The L model was the first Sidewinder with the ability to attack from all angles, including head-on. An improved active optical fuze increased the missile’s lethality and resistance to electronic countermeasures. A conical scan seeker increased seeker sensitivity and improved tracking stability. The AIM-9L is configured with an annular blast fragmentation warhead. Production and delivery of the AIM-9L began in 1976.
The AIM-9M missile utilizes a guidance control section with counter-countermeasures and improved maintainability and producibility. The AIM-9M is configured with an annular blast fragmentation warhead. Currently the only operational variant, has the all-aspect capability of the L model, but provides all-around higher performance. The M model has improved defense against infrared countermeasures, enhanced background discrimination capability, and a reduced-smoke rocket motor. These modifications increase ability to locate and lock-on a target and decrease the missile’s chances for detection. Deliveries of the M model began in 1983. Source fas.org
The AIM-7 Sparrow is a radar-guided, air-to-air missile with a high-explosive warhead. The versatile Sparrow has all-weather, all-altitude operational capability and can attack high-performance aircraft and missiles from any direction. The AIM/RIM-7 series is a semiactive, air-to-air, boost-glide missile, designed to be either rail or ejection launched. Semiactive, continuous wave, homing radar, and hydraulically-operated control surfaces direct and stabilize the missile on a proportional navigational course to the target. Propulsion for the missile is provided by a solid propellant rocket motor.
The missile has five major sections: radome, radar guidance system, warhead, flight control (autopilot plus hydraulic control system), and solid-propellant rocket motor. It has a cylindrical body with four wings at mid-body and four tail fins. Although external dimensions of the Sparrow remained relatively unchanged from model to model, the internal components of newer missiles represent major improvements with vastly increased capabilities. Sparrow is a supersonic, medium range, aerial-intercept missile, which guides on RF energy. The missile processes radar signals received directly from the launch platform’s radar via its rear signal receiver, and also processes RF energy reflected from the target received by its own internal radar receiver (front signal). Sparrow is controlled in flight by four movable delta platform wings. Missile stability is provided by four fixed delta fins which are located in line with the forward wings. Missile propulsion is provided by a dual-thrust, solid propellant rocket motor. An active RF fuze detonates the warhead when the missile is within lethal range of the target. To increase performance in either application, air-to-air or surface-to-air, Sparrow contains switching circuits that automatically program missile operation for optimum performance in the appropriate environment. The Sparrow Weapon System consists of the radar-guided missile; the support equipment consisting of test, handling, and training equipment, tools and reusable containers; and the aircraft or ship’s equipment required to launch the missile.
AIM-7F Sparrow is a supersonic, medium range, aerial-intercept missile
The AIM-7F joined the Air Force inventory in 1976 as the primary medium-range, air-to-air missile for the F-15 Eagle. The AIM-7F was an almost completely new missile, gaining ability from improved avionics that allowed the warhead to be moved to the front, allowing a bigger motor to be carried that has improved range.
AIM-7M Sparrow is a supersonic, medium range, aerial-intercept missile
The AIM-7M, the only current operational version, entered service in 1982. It has improved reliability and performance over earlier models at low altitudes and in electronic countermeasures environments. It also has a significantly more lethal warhead. The latest software version of the AIM-7M is the H-Build, which has been produced since 1987 and incorporates additional improvements in guidance. AIM/RIM-7M DT and OT was successfully completed in FY82. The F-15 Eagle and F-16 Fighting Falcon fighters carry the AIM-7M Sparrow. Source fas.org
AIM-120 AMRAAM Slammer
The AIM-120 advanced medium-range air-to-air missile (AMRAAM) is a new generation air-to-air missile. It has an all-weather, beyond-visual-range capability and is scheduled to be operational beyond 2000. AMRAAM is a supersonic, air launched, aerial intercept, guided missile employing active radar target tracking, proportional navigation guidance, and active Radio Frequency (RF) target detection. It employs active, semi-active, and inertial navigational methods of guidance to provide an autonomous launch and leave capability against single and multiple targets in all environments.
The AMRAAM weighs 340 pounds and uses an advanced solid-fuel rocket motor to achieve a speed of Mach 4 and a range in excess of 30 miles. In long-range engagements AMRAAM heads for the target using inertial guidance and receives updated target information via data link from the launch aircraft. It transitions to a self-guiding terminal mode when the target is within range of its own monopulse radar set. The AIM-120 also has a “home-on-jam” guidance mode to counter electronic jamming. With its sophisticated avionics, high closing speed, and excellent end-game maneuverability, chances of escape from AMRAAM are minimal. Upon intercept an active-radar proximity fuze detonates the 40-pound high-explosive warhead to destroy the target. At closer ranges AMRAAM guides itself all the way using its own radar, freeing the launch aircraft to engage other targets.
Presently, there are three series of AMRAAM: AIM-120A, AIM-120B, and AIM-120C.
AIM-120A. First production AIM-120A, delivered by Hughes in 1988 to the 33d TFW at Eglin AFB, Florida.
AIM-120B and AIM-120C versions are currently in production, the latter with smaller control surfaces to permit increased internal carriage capability in the F-22. AIM-120B deliveries began in FY 94, and AIM-120C deliveries began in FY 96.
P3I. An improvement program seeks to develop AMRAAM capabilities, including software reprogrammability, advanced counter-countermeasures, and options for improved propulsion.
The AIM-120A is a non-reprogrammable missile (requires a hardware change to upgrade the missile software). The AIM-120B/C is reprogrammable through the missile umbilical using Common Field-level Memory Reprogramming Equipment (CFMRE). The AIM-120C has smaller aerosurfaces to enable internal carriage on the Air Force F-22 aircraft. The USAF All-Up-Round (AUR) container houses an internal cable which enables up to four missiles to be reprogrammed while in the container. USN containers are not equipped with the cable and must be opened to reprogram the missile. All three AMRAAM variants are currently approved for use on the F-15C/D/E, F-16C/D, and F/A-18C/D aircraft. Source fas.org
Ranges for these missiles are: Sidewinder: 8km; Sparrow: 45km; and AMRAAM: 50km.
The range of air-to-ground ordnance includes guided GBU-10, -12, -15 and -24 bombs, and Raytheon AGM-65 Maverick infrared-guided missiles. Maverick’s range is 25km.
GBU-10, -12, -15 bombs
GBU-10, -12, -15
Raytheon AGM-65 Maverick
Raytheon AGM-65 Maverick infrared-guided missiles
The first units of GBU-15 glide bomb upgraded with Global Positioning System (GPS) guidance have been delivered for deployment on the F-15E. The Joint Direct Attack Munition (JDAM) was cleared for carriage on the F-15E in February 2005. The aircraft will also be able to carry the Lockheed Martin AGM-158 joint air-to-aurface stand-off missile.
GBU-15 glide bomb
GBU-15 glide bomb
AGM-158 Joint Air to Surface Standoff Missile (JASSM)
JASSM is a precision cruise missile designed for launch from outside area defenses to kill hard, medium-hardened, soft, and area type targets. The threshold integration aircraft are the F-16, B-52, and F/A-18 E/F, and the airframe design is compatible with all JASSM launch platforms: the B-52H, F-16C/D, F/A-18E/F, F-15E, F-117, B-1B, B-2, P-3C and S-3B. The weapon is required to attack both fixed and relocatable targets at ranges beyond enemy air defenses. After launch, it will be able to fly autonomously over a low-level, circuitous route to the area of a target, where an autonomous terminal guidance system will guide the missile in for a direct hit. The key performance parameters for the system are Missile Mission Effectiveness, range, and carrier operability.
Lockheed Martin AGM-158 joint air-to-aurface stand-off missile
JASSM’s midcourse guidance is provided by a Global Positioning System (GPS)-aided inertial navigation system (INS) protected by a new high, anti-jam GPS null steering antenna system. In the terminal phase, JASSM is guided by an imaging infrared seeker and a general pattern match-autonomous target recognition system that provides aimpoint detection, tracking and strike. It also offers growth potential for different warheads and seekers, and for extended range. Source fas.org
The F-15E is the first aircraft to be armed with the Boeing GBU-39 GPS-guided 113kg (250lb) small diameter bomb. Up to 12 bombs can be carried. The SDB entered Low-Rate Initial Production (LRIP) in April 2005 and achieved Initial Operating Capability (IOC) on the F-15E in September 2006.
Boeing GBU-39 GPS-guided 113kg (250lb) small diameter bomb
Boeing GBU-39 GPS-guided 113kg (250lb) small diameter bomb
The Laser Small Diameter Bomb (Laser SDB) system is the next generation of affordable and low-collateral-damage precision strike weapons, which builds on the success of the same Semi-active Laser (SAL) sensor currently used by Boeing’s Laser JDAM. A Laser SDB increases mission effectiveness in several ways:
By using already-proven laser sensor technology, Laser SDB offers the flexibility to prosecute targets of opportunity, including moving targets. With the BRU-61 Carriage System, these optimized munitions offer increased load-out for each weapons station to prosecute multiple targets per sortie. As a 250-lb. class weapon, Laser SDB’s smaller size and High Performance Wing Assembly allow it to glide for extended ranges.
Besides providing a safer standoff distance for pilots at greater than 60 nautical miles, Laser SDB target coordinates can be updated after weapon release by illuminating the target with standard Laser designation procedures. Laser SDB also retains a smaller warhead that provides reduced collateral damage, and offers ultra-low fragmentation with the composite focused lethality munition (FLM) variant. Source boeing.ca
• Dimensions: (L x W): 70.8″ x 7.5″ (1.8 m x 19 cm)
• Weapon Weight: 285 pounds (130 kg)
• Warhead: 206 lb. (93 kg) penetrating blast fragmentation
• Warhead penetration: >3 feet of steel reinforced concrete
• Fuze: electronic safe/arm fuze
• Standoff maximum range: more than 60 nautical miles
• Precision inertial navigation system/GPS
• Anti-jam GPS and selective-ability anti-spoofing module
BRU-61/A Carriage System:
• Payload capacity: four weapons
• Weight: 320 pounds (145 kg) empty, 1,460 pounds (664 kg) loaded
• Dimensions (L x W x H): 143″ x 16″ x 16″ (3.6 m x 40.6 cm x 40.6 cm)
• Fits nearly all delivery platforms
The aircraft is also armed with an internal General Dynamics M-61A1 20mm Gatling gun installed in the right wing root, which can fire 4,000 or 6,000 shots a minute.
M-61A1 20mm Gatling gun
M-61A1 20mm Gatling gun
The M61 20mm Vulcan is an externally powered, six-barrel, rotary-fire gun having a rate of fire of up to 7200 spm. The firing rate is selectible at 4,000 spm or 6,000 spm. The gun fires standard electrically primed 20mm ammunition. The M61A1 is hydraulically or ram-air driven, electrically controlled, and uses a linkless ammunition feed system.
Each of the gun’s six barrels fires only once during each revolution of the barrel cluster. The six rotating barrels contribute to long weapon life by minimizing barrel erosion and heat generation. The gun’s rate of fire, essentially 100 rounds per second, gives the pilot a shot density that will enable a “kill” when fired in one-second bursts.
M-61A1 20mm Gatling gun on F-15C
The M61 20mm cannon is a proven gun, having been the US military’s close-in weapon of choice dating back to the 1950s. The F-104, F-105, later models of the F-106, F-111, F-4, B-58, all used the M61, as does the Air Force’s F-15 , F-16 and F-22, and the Navy’s F-14 and F/A-18. The internally mounted 20mm cannon system is common to all versions of the F-15. This system combines the widely used (F-4, F-16, F-18) M61 cannon with 940 rounds (A through D models) or 500 rounds (E model) of ammunition. The cannon can be loaded with target practice, armor piercing, or high explosive incendiary rounds. The primary use of the cannon is in the extremely short range (less than 2000 feet) air-to-air environment, where more sophistacated air-to-air missiles are ineffective. Alternately, the cannon has limited usefulness in a ground strafing role. Source fas.org
Boeing Touts New 16 Air-To-Air Missile Carrying F-15 Eagle Configurations Advanced F-15 (2040c)
According to Boeing artwork floating around the net, this includes the activation of the number one and number nine weapon stations on the outer wings, or possibly by hefting a multiple ejector rack capable of carrying a pair of AIM-120 AMRAAMs on the Strike Eagle’s conformal fuel tanks. It’s speculated that some modifications have been made to the Eagle’s existing conformal fuel tank design to make this possible. Additionally, a new pylon for the Eagle’s standard wing hardpoints capable of carrying four missiles instead of two looks to be a key part of the concept.
F-15SA (Saudi Advanced): Details
See details of F-22 Raptor: HERE
The Talon HATE pod
See details of Talon HATE pod: HERE
F-15SA is the most advanced production F-15 Eagle ever built
The integrated avionics systems provide all-weather, around-the-clock navigation and targeting capability. The Raytheon APG-70 synthetic aperture radar displays high-quality images of ground targets. APG-70 is able to create and freeze the high-resolution ground maps during quick sweeps of the target area, lasting only seconds.
Upgraded Raytheon APG-63(V)3 (AESA) radar
USAF F-15Es are being fitted with the upgraded Raytheon APG-63(V)3 Active Electronically Scanned Array (AESA) radar which has a new transmitter, receiver, data processor and signal data converter. The first was delivered to Boeing for flight tests in September 2006.
F-15E demonstrates new display system: Here
APG-82(V)1 AESA radar
Delivering next-generation capabilities
The APG-82(V)1 AESA radar is the latest radar advancement for the U.S. Air Force F-15E fleet.
F-15E PLATFORM OPTIMIZATION
The APG-82(V)1 optimizes the F-15Es multirole mission capability. In addition to its extended range and improved multi-target track and precision engagement capabilities, the APG-82(V)1 offers improvement in system reliability over the legacy F-15E APG-70 radar. This phenomenal level of reliability and maintainability will result in significant maintenance cost savings for the U.S. Air Force.
By leveraging combat-proven technologies—the APG-79 and APG-63(V)3 AESA radars flying on the F/A-18E/F, the EA-18G and the F-15C platforms—Raytheon delivers a low-risk, cost-effective and superior situational awareness and attack radar to modernize the Strike Eagle.
EFFECTIVENESS AND SURVIVABILITY
Aircraft equipped with the APG-82(V)1 AESA radar can simultaneously detect, identify and track multiple air and surface targets at longer ranges than ever before. The longer standoff range facilitates persistent target observation and information sharing for informed decision making. This superior battlespace awareness supports greater tactical mission capability. The result: greatly increased aircraft-aircrew effectiveness and survivability.
PROVEN AESA TECHNOLOGY
Raytheon’s ground-breaking AESA technology has consistently proven its exceptional performance, reliability and mission capabilities for the warfighter. Our APG-79 AESA radar design, now extended to the APG-82(V)1, is combat-proven on fielded F/A-18s, and it’s being adapted now to modernize the Strike Eagle.
“The new radar system does everything faster, is extremely precise and requires less maintenance,” Riley said. “It can designate air-to-air and air-to-ground simultaneously, allowing us to track enemy aircraft and identify ground targets at the same time.”
According to the Air Force’s first RMP report, the new radar system is designed to retain functionality of the old legacy radar system while providing expanded mission employment capabilities to include:
– Near simultaneous interleaving of selected air-to-air and air-to-ground functions
– Enhanced air-to-air and air-to-ground classified combat identification capabilities
– Longer range air-to-air target detection and enhanced track capabilities
– Longer range and higher resolution air-to-ground radar mapping
– Improved ground moving target track capability
“In order to maintain our combat edge in today’s challenging environment, Air Combat Command must balance resources between refurbishing our existing fleet and investing in future weapon systems,” said Gen. Mike Hostage, the commander of ACC.
The RMP replaces the F-15E’s more than 20-year-old legacy APG-70 mechanically scanned radar with an active electronically-scanned array, or AESA, system designated as the APG-82(V)1.
“The old radar system is hydraulic, has moving parts and requires three maintainers to perform repairs after every 30 flight hours,” said Master Sgt. Jennifer Schildgen, a 366th Fighter Wing avionics manager. “The new radar system is a beam scan, doesn’t have any moving parts and is projected to only require one maintainer to perform repairs after more than 2,000 flight hours.”
The modification process is managed by Boeing representatives and takes two to three months to complete for each aircraft. The tentative plan is to complete RMP for 47 aircraft from the 389th FS and 391st Fighter Squadron by 2017.
So far, the F-15E fighter aircraft has flown more than 11 hours with the new radar. Source af.mil
Link 16 data net system
ViaSat’s team is leading the transformation in Link 16 Airborne Terminal technology by being the first to upgrade the design of many components of the terminal to provide greater flexibility, enhanced technological capabilities, decreased cost and improved reliability. Embedded modules provide COMSEC and TACAN.
Through extensive use of reprogrammable components and a modular VME architecture, we’ve provided a lower cost design while also allowing for future requirements. Our terminal provides all operational modes of the Link 16 waveform, and implements all required Multifunctional Information Distribution System (MIDS) host interfaces for both U.S. and Coalition integration. Our hardware implements Enhanced Throughput, a new capability that can increase coded data throughput from its current maximum of 115.2 kbps to over 800 kbps. Host interfaces and operational employment of this capability are still in the planning stages.
Together with Harris and European Aeronautic Defense and Space Company (EADS), ViaSat is delivering a family of combat-proven, fully qualified, and EMC-Certified Link 16 MIDS terminals to U.S. Forces and Coalition partners under contracts to the Navy MIDS International Program Office (IPO) and other commercial customers. Source viasat.com
Digital Electronic Warfare Suite (DEWS)
Image @from the web
DEWS offers full quadrant detection and response control, containing aft receiving antennas on top of the tails, aft RF transmitters and antennas built in the tailbooms, forward RF transmitters and antennas built in the leading edge of the wing roots, forward receiving antennas built in the wingtips and a low band Rx knife antenna placed on the underbelly of the jet below the cockpit.
DEWS includes a digital RWR, digital jamming transmitter, ICS and an interference cancellation system. According to Boeing, the system enables the Silent Eagle to jam enemy radars while its own radar and RWR continues to operate. Source f-15e.info
The F-15E is fitted with the Lockheed Martin LANTIRN navigation and targeting system. The LANTIRN navigation pod contains a Forward-Looking Infrared (FLIR) sensor, which produces video images that are projected onto the pilot’s HUD, and terrain-following radar. The LANTIRN system can be coupled to the flight control system for hands-off terrain, following at altitudes as low as 200ft. The LANTIRN targeting pod contains a tracking FLIR and laser designator.
Lockheed Martin LANTIRN navigation and targeting system
LANTIRN Extended Range (ER) navigation and targeting pods provide today’s warfighter with enhanced range, resolution and reliability delivering multi-mission success with a low cost of ownership. LANTIRN ER allows aircrews to operate, in daylight or darkness, at mission altitudes from sea level to 40,000 feet, all with outstanding targeting performance. LANTIRN ER, which is the latest LANTIRN production configuration, is offered as a newly fabricated pod, or as an upgrade to existing pods. Source lockheedmartin.com
The FLIR imagery, for terrain following, avoidance and navigation, is generated by a wide field of view FLIR sensor, sensor, mounted in the port LANTIRN navigation pod, together with the terrain following radar (TFR). The second LANTIRN pod, starboard mounted, is termed the targeting pod. It contains a narrow field of view FLIR sensor, boresighted with a laser rangefinder/designator and importantly, in its later versions, an automatic target recogniser. Source ausairpower.net
The FLIR imagery, for terrain following, avoidance and navigation, is generated by a wide field of view FLIR sensor, sensor, mounted in the port LANTIRN navigation pod, together with the terrain following radar (TFR). The TFR is an advanced digital system which automatically controls its power output, both in direction and time (it will build up a terrain profile in its memory, store it, switch off and turn on again only when necessary to rebuild the profile), is frequency agile and can be configured for ground mapping. The frequency agility and silent on/off operation make it very difficult to detect. The second LANTIRN pod, starboard mounted, is termed the targeting pod. It contains a narrow field of view FLIR sensor, boresighted with a laser rangefinder/designator and importantly, in its later versions, an automatic target recogniser. Source ausairpower.net
LANTIRN stands for Low Altitude Navigation and Targeting Infrared for Night. This system consists of two pods hung under the air intakes – the AN/AAQ-13 navigation pod under the right intake and the AN/AAQ-14 targeting pod under the left intake. Since LANTIRN pods are in use with other platforms (A-10, F-16) where they have other hanging points, adaptor units are needed to fix them on the F-15E. The adaptor units are the ADU-576/A for the navigation pod and ADU-577/A for the targeting pod. This is the only place on the F-15E for them and they cannot be exchanged. Although both of the pods are capable of working alone, most of the time they come in pair, an F-15E with only one LANTIRN pod is a rare sight. Source f-15e.info
AN/AAQ-13 navigation pod under the right intake and the AN/AAQ-14 targeting pod under the left intake @f-15e.info
After obtaining a radar image off the target area, the F-15E aircrew can designate targets by positioning a cursor on the radar display. The target data is transferred to the LANTIRN system for use by the tracking FLIR, which enables aiming of air-to-ground weapons from up to ten miles. Target tracking data is handed automatically to precision-guided weapons such as low-level laser-guided bombs, which can be guided to the target after release.
It contains a terrain-following ( TF) radar, a forward-looking infrared ( FLIR) sensor, plus a control computer, a power supply (the pod uses power from the aircraft’s power system) and an environmental control unit.
Both the TF radar and the FLIR are aimed at allowing the F-15E to make a high speed, low altitude penetratation of enemy airspace at night and/or in adverse weather conditions. These two systems give a powerful edge to the Strike Eagle when it comes to deep interdiction missions, thus making the jet an extremely capable night flying platform.
The AN/APN-237A terrain-following radar is located behind the round radome forming the forward end of the pod. It is a KU band radar manufactured by Texas Instruments. When operating, it constantly scans the terrain in front of the jet and combining it with using altitude and airspeed data, it is able to generate inputs to the autopilot to maintain its pre-set altitude thus making the jet follow the contours of the terrain totally ‘hands off’, that is without inputs from the pilot. When the autopilot is not in use the TF radar is able to generate maneuvering cues for the pilot to avoid ground obstacles.
Forward Looking Infrared
The LANTIRN navigation pod contains a fixed, wide file of view (21×28 degrees), advanced 3rd generation mid-wave (8-12 micron) forward looking infrared ( FLIR) sensor. The window of this sensor can be found directly above the TF radome.
This FLIR sensor generates an infrared image of the terrain in front of the aircraft and projects it onto the pilot’s HUD. This way the pilot is able to see the terrain in front of him through the HUD in shades of green even in total darkness or in adverse weather conditions. Seeing the terrain the pilot can easily fly at high speeds very close to the ground, thus using terrain features (mountains, valleys) to avoid enemy detection. The WSO can view the same image on one of his multi-purpose display, by calling up the HUD-repeater page. Note that the repeated FLIR image is available for the WSO regardless of whether the pilot had actually chosen to put the FLIR image on the HUD or not. Source f-15e.info
FLIR image @f-15e.info
Lockheed Martin created an improved version of the pod in 1995 mainly for the Navy’s F-14 Tomcats. This pod integrated the navigation and targeting features in one unit, plus brought many improvements over the previous two-pod LANTIRN system.
The targeting pod features a data-logging module ( DLM) which communicates with the pod’s control computer to provide real-time data recording and logging. Data can be analyzed after landing by connecting a portable data terminal into the appropriate socket outside of the pod. The DLM system can be of great help for the ground crew when trying to find minor or lower-level errors.
The pod contains a laser designator/rangefinder to aid the delivery of precision guided munitions (PGM’s) plus the software necessary to automatically track the selected target regardless of the maneuvering of its host plane. The designator is a four-digit PRF coded laser which can designate for the aircraft’s own weapons and for the weapons of other aircraft as well (this latter technique is called ‘buddy-lasing’). In case of unguided (‘dumb’) bombs the laser is used to determine target range and the pod feeds this input to the aircraft’s fire control system.
To be able to follow the target within wide limits, the nose section (called NESA – Nose Equipment Support Assembly) of the targeting pod can rotate, thus giving the laser a 150 degree field of regard. When the system is not operating, the nose rotates the vulnerable sensors towards the belly of the jet, thus protecting it from elements (this is especially useful during takeoff and landing when ground debris could cause severe damages to the sensors). Source f-15e.info
In August 2001, Lockheed Martin was selected to provide the Sniper XR as the new Advanced Targeting Pod for USAF F-16 and F-15E aircraft. Sniper XR (extended range) incorporates a high-resolution mid-wave FLIR, dual-mode laser, CCD TV, laser spot tracker and laser marker combined with advanced image processing algorithms.
Sniper Advanced Targeting Pod
Sniper Advanced Targeting Pod (Photo by Lockheed Martin)
It is safe to say that the AN/AAQ-33 Sniper XR (manufactured by Lockheed Martin Corporation) is the most advanced targeting pod in service in the world today. Based on its predecessor, the LANTIRN targeting pod, it is far superior in range (3-5 times the range of LANTIRN), resolution, stability and in many other parameters. The first time in the history of targeting pods, it allows pilots to pick out even individual enemy soldiers on the ground from outside jet noise ranges. It is highly reliable, having an MTBF value (mean time between failures) of over 600 (!) hours. Its hardware and software configuration featuring “plug-and-play” flexibility across services and multiple platforms, Sniper XR can be used on A-10, B-1, B-52, F-15E, F-16 and F-18 aircraft. Source f-15e.info
Northrop Grumman AN/ASQ-236 Radar Pod
The AN/ASQ-236 Radar Pod contains synthetic aperture radar that provides detailed maps for surveillance, coordinate generation and bomb impact assessment purposes. It will be operational on the F-15E Strike Eagle aircraft.
The AN/ASQ-236 Radar Pod contains synthetic aperture radar that provides detailed maps for surveillance, coordinate generation and bomb impact assessment purposes. This technology provides Combat Air Forces with the ability to precisely geo-locate points of interest and conduct surveillance activities day or night, in adverse weather conditions.
Operational on the F-15E Strike Eagle aircraft, the AN/ASQ-236 pod system is externally mounted and fully integrated with the aircraft. The radar pod is a self-contained system consisting of an antenna, inertial navigation system, and environmental cooling system. The antenna is attached to a positioner plate that allows it to move about the roll axis.
The pod design also incorporates a fully automated built-in-test, or BIT, that indicates the health of the system to the operator and maintenance crews. The BIT allows fault isolation to the line-replaceable module level enabling high system availability.
Recognizing the need for an all-weather precision geo-location and reconnaissance system with the reliability and performance inherent in Active Electronically Scanned Array radars, the U.S. Air Force with Northrop Grumman embarked on a program in the late 1990s to design, fabricate, test and field a unique radar system known as the AN/ASQ-236.
Information concerning the design, development, and production of the ASQ-236 is classified to protect critical technologies and improved operational capabilities. By leveraging the technology development associated with the F-22 Raptor, the release of this new sensor will enhance all-weather precision geo-location and provide greater surveillance and reconnaissance capabilities supporting current and future operations.
Primary function: Precision geo-location and non-traditional intelligence, reconnaissance and surveillance
Prime Contractor: Northrop Grumman Corporation
Length: 130 inches (3.302 meters)
Diameter: 20 inches (0.508 meters)
Weight: 1, 000 pounds (454 kilograms)
Date Deployed: June 2009
Operational deployment of the Sniper pod on the F-15E began in January 2005, in support of Operation Iraqi Freedom.
The aircraft is equipped with an integrated internal electronic warfare suite, including: Lockheed Martin AN/ALR-56C radar warning receiver; Northrop Grumman AN/ALQ-135(V) radar jammer; and Raytheon AN/ALQ-128 EW warner. Northrop Grumman is upgrading the ALQ-135 to band 1.5 standard. It is also fitted with a BAE Systems Integrated Defense Solutions (formerly Tracor) AN/ALE-45 automatic chaff dispenser.
The F15E is equipped with a triple-redundant BAE SYSTEMS Astronics flight control system. Using manual terrain following, navigation is possible over rough terrain at altitudes down to 200ft, at nearly 600mph, with the pilot following commands from the LANTIRN system. Automatic terrain following is accomplished through the flight control system linked to the LANTIRN navigation pod’s terrain-following radar.
F-15Es are equipped with Pratt & Whitney F100-PW-229 low-bypass turbofan engines, which provide 29,000lb of thrust per engine. Using the digital electronic engine control system, the pilot can accelerate from idle power to maximum afterburner within four seconds.
Pratt & Whitney F100-PW-229
Pratt & Whitney F100-PW-229 [Graphic by Pratt & Whitney] @f-16.net
The PW-229 variant was introduced in 1992, the first jet to be equipped with it was 90-0233. Many people say that the PW-229 was not as reliable as the PW-220, but these criticisms are often dismissed in the light of the sheer power of PW-229. In fact the power of the 229 engine is such that an F-15E flying in a clean configuration (i.e. no external ordnance and pods) and without CFT’s can even reach supersonic speed without using afterburner. This is called ‘supercruise’ ability, a term that was introduced with reference to the ultramodern F-22 Raptor!
PW-229 features an Improved DEEC ( IDEEC) and 22% more take-off thrust than its predecessor. It reacts more quickly to pilot inputs (only 4 seconds from minimum power to maximum power, compared to 7 seconds of PW-220). Its greater power and quicker reactions make the PW-229 the engine of choice among Strike Eagle pilots – especially when they are talking about missions flown with heavy weapons loads.
The PW-229 has bigger cooling requirements, hence CFT’s had to be redesigned to equip with cooling scoops that reached further than the relatively slower CFT boundary layer airflow. The PW-229 was also capable of powering an increased capacity generator.
Another big difference between these two engine types is the presence of ATDPS (Assymmetric Thrust Departure Prevention System). Only PW-229’s are equipped with this. You can read more about this further below in this article.
|– Compressor Blades
– Engine Mounting Links
– Titanium Skin Panelling
– Fire Extinguisher Container
– Engine Bay Dividing Firewall
– Corrugated Inner Skin Doubler
– Afterburner Ducting
– Main Engine Mounting Frame
|– Afterburner Nozzle Actuators
– Nozzle Shroud Fairing
– Nozzle Actuating Rods
– Afterburner Exit Nozzles
– Jet Pipe Central Tail Fairing
– Central Gearbox ( CGB)
– Jet Fuel Starter
– Engine Bleed Air Ducting
Since the F-15E being a twin engine fighter, each of the engines have its own air induction system. These systems work independently of each other. Each of these systems consist of three variable ramps, a variable diffuser ramp and a variable bypass door to control airflow from the point of entering into the inlet duct to the point of entering the engines. See the following figure.
|– First Ramp
– Second Ramp
– Third Ramp
|– Diffuser Ramp
– Bypass Door
The goal is to provide the engines an airflow as smooth and optimal as it can be. The variable ramps provide air at optimum subsonic flow to the face of the engine fan inlet within a wide range of aircraft speeds. The bypass door is used to relieve excess pressure in the inlet duct by driving excess air to the airflow outside of the aircraft if necessary.
Main material source: airforce-technology.com
Updated Jul 03, 2017