Aging Aircraft: USAF F-15 Fleet Sees Renewed Interest
“Array of Aging American Aircraft Attracting Attention” discusses the issues that accompany an air force whose fighters have an average age of over 23.5 years – vs. an average of 8.5 years in 1967. One of the most obvious consequences is the potential for fleet groundings due to unforseen structural issues caused by time and fatigue. That very fear is responsible for the #1 priority placed on bringing new KC-X aerial tankers into the fleet to complement the USA’s 1960s-era KC-135 Stratotankers.
It can also affect the fighter fleet more directly.
Following the crash of a Missouri Air National Guard F-15C aircraft Nov 2/07 (see crash simulation), the US Air Force suspended non-mission critical F-15 flight operations on Nov 3/07. While the cause of that accident is still under investigation, preliminary findings indicate that a structural failure during flight may have been responsible. In response, Japan suspended its own F-15 flights, which left them in a bit of a bind – even as Israel’s F-15s joined them on the tarmac. As the effects continue to spread and the USAF and others continue to comment on this situation, DID continues to expand its coverage of this bellwether event. A conditional restoration of the American F-15A-D fleet to flight status was soon overturned by the re-grounding of that fleet as a result of the report’s conclusions – a status that remains only been partially lifted. Meanwhile, the accident report has been released (compete with video dramatization) and the status of the remaining aircraft will have significant implications for the USAF’s future F-15 fleet size. Not to mention its other procurement programs.
Then, too, this is America. Now there’s a lawsuit.
The F-15A reached initial operational capability for the US Air Force in September 1975, and approximately 670 F-15s remain in the USAF’s inventory. Current F-15 flying locations include bases in the continental United States, Alaska, England, Hawaii, Japan and the Middle East, and the aircraft are active on the Iraqi and Afghan fronts. The Missouri Air National Guard F-15C that crashed was built in 1980.
Lt. Gen. Gary L. North, US CENTCOM Combined Forces Air Component commander, is maintaining the newer F-15E Strike Eagles on ground alert, to be used if required. Otherwise, he says he will accomplish all assigned missions using a variety of fighter, attack and bomber aircraft, and unmanned aerial vehicles. Lt. Gen. North added that:
“I worry about the health of our aging fleet and how sometimes it is not well understood by those our Airmen protect… The investigation will get to the cause of the accident.”
USAF Chief of Staff Michael Moseley was even more specific in an Oct 30/07 interview with GovExec.com:
“The F-15s and F-16s were designed and built in the late ’60s and ’70s. Some of them were produced up until the early ’80s. But they’ve led a pretty hard life of 17 years of combat. So you have to replace them with something, because we were continuing to restrict the airplanes. In the F-15 case, we’ve got the airplane restricted to 1.5 Mach. It was designed to be a 2.5 Mach airplane. We’ve got it limited on maneuvering restrictions because we’ve had tail cracks, fuselage cracks, cracks in the wings. The problem with that is – and Mike Wynne uses this analogy – it’s almost like going to the Indy 500 race practicing all the way up until Memorial Day at 60 miles an hour, and then on game day, accelerating the car out to 200 miles an hour. It’s not the time to be doing that on game day.
So in our training models and in our scenarios, we’re limiting these airplanes because they’re restricted and getting old. So there’s two parts to the recapitalization of the fighter inventory. The first part is the existing stuff is old and it’s getting broke, and it’s getting harder to get it out of depot on time. And our availability rates and our in-commission rates are going down. The ability to generate the sorties on those old airplanes is in the wrong direction.”
And Flight International:
“A USAF F-15 crashed in the Gulf of Mexico in 2002 when it broke up after the leading edge of its left vertical stabiliser detached in a high-speed dive to Mach 1.97. The pilot was killed.
The USAF says it began replacing the leading edge and upper aft portion of the vertical stabilisers during depot overhaul and has so far completed 463 of its 664 aircraft. The F-15 involved in the Missouri accident had its vertical stabilisers repaired in August 2003, the service says.”
Further investigation focused on the plane’s longerons, which connect the aircraft’s metal ‘skin’ to the frame, and run along the length and side of the aircraft. Both the Accident Investigation Board and Boeing simulations have indicated them as a possible source of catastrophic failure; indeed, DID had wondered why structural failure was suspected immediately, and it with that revelation it began to make sense. As DID explained at the time, if one or more of those longerons had failed, the stresses on the airframe could have folded or broken the plane in half – a very unusual form of accident. Eventually, the publication of the formal report confirmed that hypothesis:
“The one longeron, already not up to design specifications, cracked apart under the stress of a 7G turn, the colonel said. This led to the other longerons failing as well, which then caused the cockpit to separate from the rest of the fuselage. The pilot was able to eject, but suffered a broken arm when the canopy snapped off.”
Nor is this problem confined to the USA – or even to the here and now.
The Chinese government’s Xinhua agency reports that Japan has also grounded its F-15 fleet. Japan’s F-15Js were built locally under license, on a more recent production schedule, but their oldest planes do date back to 1980. This is a precautionary measure until more is known.
Since Japan’s F-16-derived F-2 fighters are also grounded in the wake of a recent crash at Nagoya, this leaves 1960s era F-4EJ ‘Kai’ Phantom IIs as Japan’s interceptor and fighter patrol fleet for the time being.
Israel confirmed to Flight International that it had also grounded its 70 F-15A-D air superiority aircraft, which are undergoing multi-role conversions, and its F-15I Strike Eagles. The Strike Eagles were later removed from the USA’s concern list, but its F-15 A-D fleet is an important component of Israeli air defenses alongside its larger F-16 fleet.
Gen. John D.W. Corley, the commander of US Air Combat Command, was not encouraged by the results of the report, and of the in-depth fleet inspections that led to 40% of the Eagle fleet remaining on the ground over 3 months after the investigation:
“The difficulty is that issues have been found with F-15s built between 1978 and 1985, across A through D models at several bases, so no one source of the problem can be isolated… This isn’t just about one pilot in one aircraft with one bad part… I have a fleet that is 100 percent fatigued, and 40 percent of that has bad parts. The long-term future of the F-15 is in question… We don’t have a full and healthy fleet, so we’ve gotten behind on training missions, instructor certifications, classes and exercises…
We’re going over each and every aircraft to make a determination. We will take some F-15s out of the inventory. It just doesn’t make sense to spend the time and money if it won’t be worth it for some aircraft.”
December 6/18: Japan Japan’s planned upgrade of its Boeing F-15 Eagle fighter jets will likely be supported by the US government and Boeing under the Foreign Military Sales process. Japan’s Mitsubishi Heavy Industries delivered some 213 license-built F-15 variants the country’s air force between 1981 and 1999. Some 200 remain in service, of which about 88 were continuously upgraded over the past decade, gradually incorporating additional improvements like Link 16. Tokyo now plans to upgrade two of its F-15J/DJ interceptors at a cost of $89 million. According to Defense News, the upcoming upgrades include new electronic warfare equipment, and larger weapon load out – increasing the number of missiles the aircraft can carry – and the integration of the AGM-158 JASSM. Shigeyuki Uno, the principal deputy director of the defense planning and programming division of Japan’s Ministry of Defense, also told Defense News that the F-15s radar will also be upgraded, which will likely involve the AN/APG-63(V)3 or the AN/APG-63(V)1, both are AESA radars produced by Raytheon. Japan’s midterm defense program guidelines, to be released by the end of 2018, are expected to provide more details on this program, including the number of F-15s Japan plans to upgrade.
November 28/18: Qatar The Qatar Emiri Air Force expects to receive its first batch of F-15QA fighter jets by March 2021. This will be the first batch of the 36 unit order, with the remainder to be delivered in batches of four every three months. Qatar’s new F-15s will come with a totally remodeled cockpit featuring large panel touch screen displays and a new HUD display. Deputy Prime Minister and Minister of State for Defense Affairs Dr. Khalid bin Mohamed al-Attiyah inaugurated the F-15QA production line at Boeing’s St. Louis factory in August 2018. Qatar’s $12 billion F-15 order is part of a general drive to strengthen the country’s air power, which also includes the purchase of 12 Dassault Rafales and 24 Eurofighter Typhoons.
November 22/18: Israel The Israel Air Force (IAF) is set to acquire upgraded F-15s to supplement its fleet of F-35 ‘Adir’ fighter aircraft. The squadron of F-15IAs will include certain stealth capabilities, such as radar-absorbing paint and internal weapons carriage. The fighter jets will be capable of carrying 11 missiles, in addition to 28 heavy, smart bombs for ground targets. Other additions include Raytheon’s AN/APG-63(V)3 AESA radar, a long-range infrared search and track (IRST) sensor system, allowing for a “first sigh-first shot-first kill” capability and a helmet cueing system. With this upcoming purchase, Israel will be the third Middle-Eastern country to do so. Both Saudi Arabia and Qatar have ordered their respective SA and QA variants which are the most advanced Eagles in the world. However experts say that Israel’s Eagle will be even more capable and advanced than the others. The upcoming deal marks the first Boeing fighter jet acquisition by the Israeli Air Force in two decades, with the first F-15IA expected to arrive in Israel as soon as 2023. The IDF says the new F-15 will not completely replace the F-35 stealth fighter, but is intended to reinforce the systems currently in place to enhance the range of capabilities to an optimal position vis-à-vis its missions—from Iran to Gaza.
November 5/18: Saudi maintenance Boeing is being tapped to continue maintenance support for the Royal Saudi Air Force’s fleet of F-15 fighter aircraft. The company is being awarded with a $14.6 million contract that sees for the sustainment of the Aircraft Maintenance Debrief System (AMDS). The F-15 is an all-weather, extremely maneuverable, tactical fighter designed to achieve aerial superiority in combat situations. The contract allows Boeing to provide trained personnel to use and maintain AMDS equipment at six locations throughout Saudi Arabia. The company’s staff also train RSAF members on how to operate and maintain the equipment. Work will be performed at multiple locations in Saudi Arabia and is expected to run through November 4, 2023.
October 4/18: QEAF Pilot Training Boeing is being contracted to support the training of future Qatar Emiri Air Force pilots. The company will provide Qatar with F-15QA aircrew and maintenance courseware at a cost of $30 million. This includes syllabi, a student tracking system and the overall program management needed to train the country’s future F-15QA pilots. Production of the new F-15s started in August and will run through to at least 2022. Qatar ordered a total of 36 fighter jets at a cost of $12 billion. Work will be performed at Boeing’s location in St. Louis, Missouri, and is expected to be completed Dec. 28, 2020.
September 27/18: Saudi Arabia General Electric is being contracted to keep the Royal Saudi Air Force’s Strike Eagles flying. The company will provide the RSAF with F110-129 engine consumables, spares, war-readiness spare kits, and support equipment. The deal falls under the US FMS program and is priced at $58.6 million. The F-15SAs are currently the most advanced F-15 Eagles on the planet. In 2015 Saudi Arabia ordered 84 new build F-15SAs and close to 70 kits to upgrade their existing F-15S fleet to the SA configuration. GE’s F110-129 two-spool afterburning turbofan engine delivers of to 29,000 pounds of thrust and powers more than 75% of US Air Force single-engine F-16s. Work will be performed at GE’s factory in Cincinnati, Ohio, and is expected to be completed by September, 2020.
August 28/18: Legion Pod The US Air Force plans to integrate a new IRST system on its fleet of F-15C aircraft. Boeing will provide the Air Force with engineering, manufacturing, and development efforts of the F-15 Legion Pod. The contract has a value of $208.2 million and will run through November 2020. The Legion Pod is being developed in conjunction with Lockheed Martin. The pod features Lockheed’s IRST21 infrared sensor and advanced data processing capabilities. This multi-function sensor system has been designed to provide long-range detection and tracking of airborne threats in radar-denied environments. The common interface of the Legion pod allows it to be easily integrated onto any aircraft without affecting the aircraft’s operational flight programme. Work will bet performed at Boeing’s facilities on St. Louis, Missouri and Orlando, Florida.
August 6/18: Qatari production line Boeing is currently in the process of manufacturing several F-15 fighter jets for Qatar. Deputy Prime Minister and Minister of State for Defense Affairs Dr. Khalid bin Mohamed al-Attiyah recently inaugurated the F-15QA production line at the company’s plant in Missouri. Qatar’s new F-15s will come with a totally remodeled cockpit featuring large panel touch screen displays and a new HUD display developed by BAE systems. The F-15QA, is identical to the F-15SA that Boeing is building for the Royal Saudi Air Force. It has a fly-by-wire flight control system, digital electronic warfare (EW) suite, an infrared search and track (IRST) system, and the Raytheon APG-63(v)3 active electronically scanned array (AESA) radar. In a typical escort configuration, the Advanced Eagle can carry 16 AIM-120 AMRAAM, four AIM-9X Sidewinder short-range missiles; and two High-Speed Anti-Radiation Missiles. Neither the Qatari MoD nor Boeing disclosed when deliveries of the F-15 (Qatar Advanced) Eagle will begin, but it has been disclosed that they will run through to the end of 2022. The Middle-Eastern nation ordered a total of 36 fighter jets at a cost of $12 billion.
July 30/18: A squadron for Israel The Israeli Air Force is currently in negotiations with Boeing regarding a deal with a potential value of up to $11 billion. This deal would be the IAF’s largest-ever acquisition, considerably boosting its mobility and strike capabilities. Israel Hayom daily reports that the deal includes a squadron of F-15 jets with upgraded stealth features, a squadron of transport helicopters and KC-46 tanker aircraft. Israel’s outdated CH-53 Sea Stallions will likely be replaced by CH-47 Chinooks and V-22 Ospreys. The purchase will be funded from US military aid money, which comes to some $3.8 billion annually, over the next decade as the new planes and helicopters are delivered. If the deal goes through and Israel returns to purchasing F-15s, it would mark the first Boeing fighter jet acquisition by the Israeli Air Force in two decades. In the years since, Israel has bought 100 F-16s and another 50 F-35 stealth jets from Boeing’s chief competitor, Lockheed Martin.
July 13/18: Saudi support The Kingdom of Saudi Arabia is set to receive support for its F-15 Fleet Modernization program as part of a US foreign military sale. Titan LSC has been awarded a $68.4 million indefinite-delivery-requirements contract that provides for the acquisition of various different commercial vehicles and trailers in support of the RSAF program. Titan will facilitate delivery to the Dhahran Supply Depot at King Abdul Aziz Air Base and maintain operations in the Dammam Metropolitan Area in Saudi Arabia as a liaison for the operation. In October 2010 Saudi Arabia negotiated a $30-60 billion arms package with the USA including an order of 84 F-15 Strike Eagles. Work will be performed at Titan LSC, Amman, Jordan, and in the subcontractor’s facility in the Kingdom of Saudi Arabia. The contract is expected to be completed by July 10, 2021.
July 3/18: Vertical stabilizers The Air Force is contracting Boeing in support of its F-15 fleet. The firm-fixed-price contract provides for the production of F-15 vertical stabilizers and is valued at $23.6 million. The F-15A reached initial operational capability for the US Air Force in September 1975, and approximately 670 F-15s remain in the USAF’s inventory. Vertical stabilizers serve two basic purposes: flight stability and aircraft attitude alteration in yaw direction (i.e. yawing the aircraft left or right). In addition, they provide perfect mounting place for RWR and ECM antennae (located on the top of each stabilizers). Location of performance is at the company’s location in Missouri and is scheduled for completion by May 31, 2022.
April 03/18: AESA orders for USAF Boeing has been awarded a modification to a previously awarded contract for the US Air Force’s F-15 Fighter Modernization Program (RMP) radar upgrades. The contract is valued at over $187 million. It provides for work on 29 Group A and Group B kits, spares, fuel tanks and other equipment and services. The F-15A reached initial operational capability for the US Air Force in September 1975, and approximately 670 F-15s remain in the USAF’s inventory. Current F-15 flying locations include bases in the continental United States, Alaska, England, Hawaii, Japan and the Middle East. The RMP development and testing began in January 2011. The RMP replaces the F-15 legacy APG-70 mechanically scanned radar with an AESA system designated APG-82(V) and is designed to retain functionality of the legacy radar system while providing expanded mission employment capabilities including longer air-to-air target selection and enhanced task capabilities and enhanced air-to-ground and air-to-air combat identification capabilities. Work will be performed in St. Louis, Missouri, and is scheduled for completion in April 2022.
February 26/18: New wing for Qatar’s FMS F-15QA fighter aircraft being produced for Qatar will come with a newly designed wing, as manufacturer Boeing prepares to offer the design option for any future structural upgrades ordered for the US Air Force’s F-15Cs. Speaking to Flight Global, Steve Parker, Boeing’s vice-president of F-15 programs said the QA variant introduces a number of previously-announced features, including an advanced cockpit system with a large format display, and that the redesigned wing will strengthen the internal structure of the fighter without changing its aerodynamics. If the USAF decide to keep its F-15Cs flying for another two decades, the new features will be offered as part of any service life extension work ordered, and could also be offered to any other operators of F-15 aircraft, such as Japan.
June 16/17: Despite a spat with its Arab neighbors amid claims they were funding terrorism, Qatar has completed negotiations with Boeing to move ahead with a purchase of 36 F-15QA fighter aircraft. Qatari Defense Minister Khalid Al-Attiyah was in Washington to sign the $12 billion Foreign Military Sale agreement with his counterpart Jim Mattis, and could be extended to cover a total of 72 planes at a cost of approximately $21 billion. The move may confuse Washington’s allies in the region, after President Trump has initially sent a series of tweets that appeared to take credit for and praise the decision when Saudi Arabia and several Arab countries cut off ties with Qatar. “The nation of Qatar, unfortunately, has historically been a funder of terrorism at a very high level,” Trump said in a speech at the White House last week. “We ask Qatar, and other nations in the region to do more and do it faster.
March 19/17: The Israeli Air Force is considering a procurement of advanced F-15 jets from Boeing instead of purchasing additional F-35s. Tel Aviv will evaluate and consider this advanced version, capable of carrying more missiles and potentially in line with Boeing’s suggested 2040 configuration, and could order as many as 20-25 aircraft to augment its F-35 fleet. At present, the IAF has plans for a 50-strong F-35I fleet.
December 12/16: Engineers from Boeing have been working on USAF F-15Es, replacing old APG-70 radars with the state-of-the-art APG-82 AESA radar. The work has been underway since September on planes located at Seymour Johnson Air Force Base, North Carolina. Dubbed as the RMP Eagle modernization program, more than 90 jets will receive the overhaul which is expected to be completed within the next seven to nine years.
November 7/16: Boeing landed a $479 million USAF contract for engineering, manufacturing, and development of the Eagle Passive/Active Warning and Survivability System for the F-15 Eagle fighter jet. The system will provide advanced aircraft protection, significantly improved situational awareness and support for future F-15 mission requirements, replacing the jet’s Tactical Electronic Warfare Suite and keeping the aging aircraft in scheduled service through 2040. As 413 F-15Cs and F-15Es will be upgraded under the program, the expected costs may run to $7.6 billion.
October 12/16: The USAF has tasked Boeing with selecting a supplier for a $198 million upgrade of the F-15C/D which will allow the fighter to detect at long range the heat generated by an aircraft engine. After selecting the infrared search and track (IRST) sensor supplier, Boeing will be tasked with integrating the pod with the F-15’s other systems, including the Raytheon-supplied active electronically scanned array (AESA) radar. By delegating such work, the USAF avoids giving losing bidders a chance to protest Boeing’s decision to the US Government Accountability Office (GAO).
September 19/16: A recently released White House fact sheet on US military aid has revealed that Israel is to get ten F-15Ds under the excess defense articles program. Eight F-15s have been delivered so far, and are primarily used as a training aircraft but can also take part in air-to-air combat. Other excess articles given by the Obama administration to Israel include several Lockheed Martin C-130 cargo aircraft, AGM-114 Hellfire missiles and joint direct attack munitions.
May 2/16: USAF’s fleet of more than 500 F-15s are to get a wheel and brake upgrade after successful flight testing. Once completed, F-15C/D/E fighters will be capable of undertaking 1,400 landings before having to swap out their brakes. The USAF stands to save over $194 million in F-15 maintenance costs once all of the aircraft are fitted with the upgrade, and this will be the first brake testing to be carried out on the jet since the 1980s.
May 26/09: Aviation Week reports that the USAF is looking into the possibility of a Service Life Extension Program for its F-15A-D fleet, designed to increase their service lives from 8,000 flight hours to 12,000.
The move is driven, in part, by the impending collapse of Air National Guard wings that can be used in domestic air sovereignty patrols, as older fighters retire and are not replaced. The USAF is accelerating the retirement of 250 F-16 and F-15 fighters in FY 2010, and current plans calls for 2 ANG air sovereignty mission units to get F-22s, 4 to get receive upgraded F-15A-Ds, and the remaining 12 are yet to be determined.
March 22/08: Maj. Stephen Stilwell, a pilot for Southwest Airlines whose Missouri Air National Guard F-15C’s mid-air crackup began the fleet groundings, has filed suit in U.S. District Court against claiming Boeing Corp. His injuries left him with a 10-inch metal plate in the injured arm and shoulder, and he reports that he has suffered from chronic pain since the accident.
Stilwell’s suit, filed by attorney Morry S. Cole, says that Boeing knew or should have know that the F-15 as manufactured allowed and permitted for catastrophic flight break-up, and adds that Boeing failed to notify the Air Force and Missouri Air National Guard of “the likelihood of excess stress concentrations, fatigue cracking, structural failure and in-flight aircraft break up as a result of the structural deficiencies.” St. Louis Post-Dispatch.
February 2008: The largest effects of the F-15 fleet’s grounding may yet play out on the procurement front. If many of the USAF’s F-15s, which were supposed to serve until 2025 or so, must be retired, how should they be replaced? Read “Aging F-15s: Ripples Hitting the F-22, F-35 Programs.”
Jan 21/08: This week’s edition of the “Today’s Air Force” show highlights how the Air Force carried on its mission while more than 700 of its F-15 Eagles were grounded. See “The Eagle flies once again!” on the Pentagon Channel, American Forces Radio and Television Service stations around the world, and video podcast [30 minutes].
Jan 14/08: Officials begin flight operations again as 39 of the 18th Wing F-15C/Ds at Kadena Air Base, Japan are cleared to fly again after remaining on the ground for more than 2 months as a result of a fleet-wide stand-down. See USAF story.
Jan 10/08: According to the Air Combat Command Accident Investigation Board report released on this day. Their conclusion? The plane was simply too old:
“…a technical analysis of the recovered F-15C wreckage determined that the longeron didn’t meet blueprint specifications. This defect led to a series of fatigue cracks in the right upper longeron. These cracks expanded under life cycle stress, causing the longeron to fail, which initiated a catastrophic failure of the remaining support structures and led to the aircraft breaking apart in flight… the pilot’s actions during the mishap sequence were focused, precise and appropriate. The pilot’s actions did not contribute to the mishap, said Colonel Wignall. In addition, a thorough review of local maintenance procedures revealed no problems or adverse trends which could have contributed to the accident.”
Col. William Wignall, the head of the accident investigation added that:
“We’ve had great involvement from Boeing during the investigation. In fact, they’re the ones who determined the longeron was the problem. This was then confirmed by the Air Force Research Laboratory.”
Jan 9/08: Air Combat Command officials clear 60% of the F-15A-D fleet for flying status, and recommends a limited return to flight for those planes that have cleared all inspections. The decision follows detailed information briefed on Jan 4/08 to Air Combat Command from the Air Force’s F-15 systems program manager, senior engineers from Boeing and the Warner Robins Air Logistics Center; as well as a briefing received on Jan 9/08 from the Accident Investigation Board president.
The USAF report describes inspections as “more than 90% complete,” with remaining inspections focusing primarily on the forward longerons. Thus far, 9 other F-15s have been found with longeron fatigue-cracks, and almost 40% of inspected aircraft have at least 1 longeron that is thinner than blueprint specifications. ACC believes each affected F-15 will have to be analyzed to determine if there is sufficient strength in the non-specification longeron, and this analysis will take place at the Warner-Robbins Air Logistics Center over the next 4 weeks. A number of F-15s are scheduled to be retired in 2009, and calculating the cost of fixes and airframe life of fixed aircraft could have a substantial bearing on the size of the USAF’s future F-15 fleet.
Meanwhile, the 2-month grounding, which has been the longest of any USAF jet fighter, is a gift that keeps on giving. Fully 75% of US Air Force and Air National Guard F-15A-D pilots have lost their currency status for solo flight, and another week would have made it 100%. Instructor pilots have retained their currency and will begin flying F-15B/Ds with the other pilots, so the pilots can land the plane and regain their status. This will be followed by further pilot training, which is required to regain operational proficiency status. USAF report | Flight International.
Dec 27/07: The Associated Press details some of the ripple effects created by the F-15 A-D grounding. With the F-15s in Massachusetts out of commission, the Vermont Air National Guard (ANG) is covering the whole Northeast. The Oregon ANG’s fighters are grounded, so the California Air National Guard is standing watch for the entire West Coast plus slices of Arizona and Nevada. To meet that need, the Fresno, CA based 144th Fighter Wing has had to borrow F-16s from bases in Indiana and Arizona and trim back training.
The Minnesota ANG is manning sites in Hawaii, while the Illinois ANG covers Louisiana. In Alaska, the new F-22 Raptors are stepping in – and so are Canadian CF-18s, which have intercepted several Russian bombers near Alaska in recent weeks.
Dec 10/07: The F-15 A-Ds remain grounded. A USAF update informs us that throughout the Air Force, maintainers have found cracks in the upper longerons of 8 F-15s so far: 4 from Air National Guard 173rd Fighter Wing, Kingsley Field, OR; 2 from USAF 18th Wing, Kadena Air Base, Japan; 1 from 325th Fighter Wing, Tyndall AFB, FL; and 1 from ANG 131st Fighter Wing, St. Louis, MO.
Inspections are underway using previous methods, until the Warner Robins ALC develops new ones for the fleet. After the area’s paint is stripped and bare metal is exposed, Airmen apply chemicals that reveal cracks under a black light. “Other inspections in hard-to-see areas are done with a boar scope [sic… maybe they mean “borescope”?] – a tool that uses a tiny camera and fits in tight areas.” Inspection time per aircraft is 12.5 to over 20 hours, and the 2-seat B and D models are more time consuming because the rear seat must be removed to access the upper longerons. USAF story.
UPDATE from USAF: “Yes, other readers pointed that out as well (although yours was the funniest). The story was corrected…”
Dec 3/07: It’s now official. Gen. John D.W. Corley, the commander of Air Combat Command orders the stand-down of all ACC F-15 A-Ds until further notice, and recommends the same for all other branches of the USAF. The stand-down does not affect the F-15E Strike Eagle and its variants abroad.
Technical experts with the Warner Robins Air Logistics Center at Robins Air Force Base, GA are developing a specific inspection technique for the suspect area, based on the recent findings. However, unlike previous inspections, the inspected aircraft will not be returned to flight until the F-15 A-D model findings and data have been analyzed, required inspections have been accomplished, and the necessary repair or mitigation actions have been completed. To date, longeron cracks have been discovered in an additional 4 aircraft. USAF release.
Nov 28/07: The accident investigation board (AIB) report leads to the recommended re-grounding of the USAF F-15 A-D fleet, and almost certainly those of other countries as well. The new AIB findings have drawn attention to the F-15’s upper longerons near the canopy of the aircraft, which appear to have cracked and failed. Longerons connect the aircraft’s metal ‘skin’ to the frame, and run along the length and side of the aircraft. In addition to the AIB’s conclusions, manufacturer simulations have indicated that a catastrophic failure could result from such cracks, which were also discovered along the same longeron area during 2 recent inspections of F-15C aircraft.
The commander of Air Combat Command has recommended the stand-down of all F-15 A-D model aircraft across the US military, and ordered a renewed fleet-wide inspection of all ACC F-15 A-D model aircraft using a very specific inspection technique for the suspect area. The multi-role 2-seat F-15E Strike Eagles, which were manufactured later and had several design changes made, remain exempt from these cautions and exceptions. USAF article.
Nov 21/07: All USAF’s F-15s are being returned to flight status, despite acknowledgment that the service is accepting a degree of risk in doing so. Gen. John D.W. Corley, commander, Air Combat Command:
“The cause of the mishap remains under investigation… At the same time, structural engineers have conducted in-depth technical reviews of data from multiple sources… First, we focused on the F-15Es. They are… structurally different than the A-D models. Problems identified during years of A-D model usage were designed “out” of the E-model… Next, we concentrated on the remainder of the grounded fleet. The AIB(Accident Investigation Board) is now focused on the area just aft of the cockpit and slightly forward of the inlets. Warner Robins ALC mandated a thorough inspection and repair of all structural components in this area. I have directed each F-15 aircraft be inspected and cleared before returning to operational status. Today, ACC issued (a flight crew information file) and Warner Robins ALC issued an Operational Supplemental Tech Order to further direct and guide your pre-flight and post-flight actions.”
There are 666 F-15s in the Air Force inventory. As of this day, 219 of the 224 E-models and 294 of the 442 A-D models in the USAF’s inventory have been inspected and re-cleared for flight.
Nov 19/07: Shortly after becoming the first deployed F-15E unit in the Air Force to return to full operational capability following the Air Force’s fleet-wide grounding of the aircraft, the 455th Expeditionary Maintenance Squadron at Bagram AFB, Afghanistan, began the move from 5-7 day phase inspections every 200 flight hours, to a phase inspection every 400 flight hours. This change isn’t slated for implementation until 2008, but it’s being implemented early at Bagram AFB to keep more F-15Es in the air and meet mission demands.
The USAF says that its engineers at the Warner-Robins Air Force Base Air Logistics Center, GA looked carefully at all the data after years of F-15E analysis and testing, before approving the change. USAF release.
Nov 15/07: A USAF release says that an order issued by Air Combat Command’s Commander Gen. John Corley on Nov 11/07 mandates a 13-hour Time-Compliance Technical Order (TCTO) on location for each of the USAF’s F-15E Strike Eagles, to inspect hydraulic system lines, the fuselage structure, and structure-related panels. Aircraft that pass this inspection may return to flight status, and similar procedures are likely to be underway for Israel’s F-15Is. ACC Combat Aircraft Division chief Col. Frederick Jones said that this was possible because:
“We were able to determine, based on initial reports from an engineering analysis, that the F-15E is not susceptible to the same potential cause of the Missouri mishap.”
The TCTO inspection is designed to confirm the engineering analysis, and aircraft deployed the CENTCOM has apparently completed inspections and returned to flying status. This still leaves 2/3 of the USAF’s F-15 fleet grounded, however, as the F-15A-D models remain under suspicion. The F-15Es are about 15 years old on average, but the F-15A-D models were introduced earlier. Maj. Gen. David Gillett, ACC director of Logistics said that:
“What we’ve got here is an example in the C model of what happens when you have an airplane that’s about 25 years old… What you find is that it becomes more and more expensive to modify [the F-15 airframe] over time… Our costs have gone up 87 percent in the last five years and continue to rise rapidly. Even when you invest in an old airframe – you still have an old airframe.”
Additional Readings & Sources
- Gannett’s Military Times – F-15’s midair breakup. Hosts the Pentagon’s Crash Simulation.
- DID Spotlight article – Aging Array of American Aircraft Attracting Attention. The problem is not at all unique to America.
- Reuters (Oct 15/08) – US Air Force eyes fighter cuts to boost modernization. The force cuts would reduce the reserve fleets by about 137 F-15s, but it would also cut 177 F-16 fighters and 9 A-10s. The goal is to save $3.4 billion, to be applied to F-35 purchases.
- Investors Business Daily (Dec 7/07) – The Eagles are Grounded. Quotes ACC chief Maj. Gen. Ronald Keys re: the slippage of fighter fleet average age from 1967 to the present.
- Flight International (Nov 6/07) – VIDEO: Israel and Japan join US in grounding F-15s
- USAF (Nov 6/07) – Mission continues during grounding of F-15s.
- US DoD DefenseLINK (Nov 6/07) – Air Force Grounds F-15 Fleet Following Crash
- Xinhua, via Military.com – Now Japan Grounds F-15 Fighters
- USAF (Nov 4/07) – Air Force suspends some F-15 operations