boeing t x or t 7 red hawk prototypes on taxiway in 2018

On Tuesday, Boeing announced that it had completed taxi-tests for its five newly built T-7A Red Hawk trainer jets. They’re currently located at Lambert field in St. Louis, Missouri. That leaves the way clear for a first flight of this second-phase iteration of the supersonic jet trainer in the coming days or weeks—though, bear in mind, Boeing began flying two precursor prototypes of the T-7 way back in December of 2016.

In a press release, Boeing’s chief test pilot Steve Schmidt stated that “the flight controls and commands to the fly-by-wire system were crisp and the aircraft maneuvered exceptionally well. Everything operated as designed and expected.”

Unfortunately, that last remark can’t be extended to the T-7’s development process as a whole, as it has fallen well behind schedule. A recent report by the Government Accountability Office (GAO), the government’s top watchdog agency, suggests the Pentagon and Boeing may be in need of something akin to marriage counseling over the year-long delays in finalizing the company’s T-7A Red Hawk trainer that could cost the Air Force billions.

The report notes Boeing and the Air Force have differing interpretations of the former’s contractual obligations, and characterized their relationship as “tenuous.” The company has run up over $1.1 billion in losses trying to correct problems.

Like the more seriously troubled KC-46 Pegasus tanker, the T-7 is a Boeing project that initially seemed like a slam dunk, but has accumulated significant costs and delays due to unanticipated problems with subcomponents.

The biggest source of the delays? Tests show the Red Hawk’s ejection seat handling crash test dummies lower in the weight range roughly. There have also been difficulties perfecting the T-7’s digital flight control system, finalizing training simulators, and producing a clear accounting of sustainment requirements.

Sources cited by the report said the relationship improved when the Pentagon chipped in to fund some of the needed additional tests, but those sources expected that good will to deteriorate again as Boeing is required to pay for future tests.

To be fair, a “top Air Force official” later insisted to Breaking Defense that they had an “actually fantastic” relationship with Boeing after publication of the GAO report on May 18, and expressed optimism that there remained enough “flexibility” in the schedule to attain objectives on schedule.

For now, some of the five new T-7As are slated to begin flight tests at Lambert Field in St. Louis this summer. They will then be transferred to Edwards Air Force base in California for further evaluations.

usaf northrop t 38a talon taxiing with both canopies open and spoiler deployed

Boeing’s T-7 is based on a clean sheet designed and developed for the T-X competition, which sought to find a replacement for its more than 400 Norhtrop T-38 Talon supersonic jet trainers. This over-60-year-old design has served well, but is running long in the tooth and lacks the avionics to enable trainees to practice new capabilities widely used on Air Force jets. The new jet trainer would also come with hi-tech simulators that would further reduce training costs.

In September of 2018, Boeing’s two single-engine T-X prototypes—with tails reminiscent of the FA-18 Super Hornet jet—defeated rival proposals based on the F-16-like T-50 jet trainer and Italian MB-346, in part by competing aggressively lower on price. In 2019, the design was officially designated the T-7 Red Hawk in tribute to the Black World War II fighter pilots of the 99th Fighter Squadron.

tuskegee airmen of 99th squadron in italy

Black Tuskegee airmen assembled around a P-40 Warhawk fighter deployed for combat in the Mediterranean during World War II. Initially assigned ground attack duties by racist superiors, the 99th eventually undertook air superiority and bomber escort missions over Italy and Central Europe with great success. Presumably this Warhawk bears the unit’s signature red-painted tail.

Wikimedia Commons

The plan was for Boeing to produce around 351 T-7As, along with 46 simulators, at their factory in St. Louis, Missouri. Partner Saab was to contribute aft sections of the aircraft, mostly from a new facility in Indiana. This order—produced in 11 lots between 2025-2034—would cost a total of between $7.2 billion and $9.2 billion, with a unit price per plane of $21.8 million. Technically, the contract could be optioned out to 473 aircraft and 120 simulators.

Boeing hopes to also eventually export over 2,000 T-7s abroad, some of which might be evolved into a light fighter aircraft configuration similar to the FA-50. Pitches have already been made to Australia, Brazil, and Serbia. Furthermore, the Air Force may procure an additional 100 T-7s to fulfill a requirement for an Advanced Tactical Trainer, particularly for use as ‘bad guy’ aggressor aircraft used for training. The T-7 is also being offered to meet a similar U.S. Navy requirement for 64 such ‘surrogate’ aircraft.

boeing at 53rd paris air show

But before scooping up more sales, Boeing needed to finalize a production model jet in the Engineering Manufacturing and Development (EMD) phase for which it could leverage digital design tools that would require much less costly prototyping. These included high-accuracy automatic drilling technology called ‘determinant assembly,’ which reportedly reduced hours needed for aircraft assembly by 80% and facilitated construction of five new pre-production aircraft. These new techniques led to a (thankfully short-lived) attempt to brand the jet Silicon Valley-style as the eT-7.

This content is imported from youTube. You may be able to find the same content in another format, or you may be able to find more information, at their web site.

Attack of the Crash Test Dummies

The rapid pace of T-7 development, however, slowed due to unsatisfactory test results of the aircraft’s ejection seat.

The ejection mechanism is designed to automatically blast the canopy glass above the pilot open and outward before rocketing them to safety using a Collins Aerospace ACES 5 ejection seat. As a backup, the canopy is also designed to shatter on contact, with breakers built into the pilot’s seat during ejection. Software then calculates when it’s safest to release the parachute and drop the seat from under the pilot.

An ejection systems’ safety is evaluated in sled tests, in which a sensor-laden crash-test dummy clad just like a real life fighter pilot sits in a real ejection seat and simulated cockpit atop a rocket-powered sled. This sled is then propelled down hundreds of meters of rail at a few hundred miles per hour until the ejection system is activated. The results are recorded using multiple cameras and other sensors. Many of these tests were conducted by the 846th Test Squadron using its HHST facility at Holloman Air Force base in New Mexico, with findings transmitted in real time to Boeing.

While the force generated by T-7’s system hit “barely acceptable” levels of injury for crash test dummies representing heavier pilots, it was inflecting unacceptable levels roughness on lighter-weight manikins that may be more representative of female pilots. Here, “roughness” means “risk of concussion upon ejection, body acceleration that could result in spinal injury, and eye and neck injury.”

Each unsatisfactory test requires adjustments and more tests. And they aren’t cheap: a $9 million dollar contract, for example, funded just four tests.

boeing t 7 ejection system in gao report

Illustration from GAO report of T-7A’s ejection system.

Wikimedia Commons

Until the ejection seat problems are deemed fixed, Air Force personnel legally can’t fly the planes—or even receive them—which holds up the process of issuing a production contract.

According to the report, the problems (and solutions) boil down to:

  • The blast of the canopy fracturing system is causing overpressure sufficient to cause a concession in 20% of simulated escapees instead of the target threshold of 5%. Reducing the amount of explosives, and changing its location, may reduce the overpressure adequately.
  • In several tests, “large canopy fragments stuck to the test manikins”
  • The seat has to be perfectly aligned with the pilot’s spinal chord, or high G-forces risks causing “injury or death” when the parachute is deployed.

Reportedly, tweaks to the parachute systems software and how it evaluates deceleration of the pilot have already made progress in reducing this risk. The overall revisions to the ejection system, however, are expected to require seven more tests.

Boeing and the Air Force also don’t see eye to eye on the T-7’s flight control software, which interprets the pilots joystick commands while compensating for other aerodynamic factors. Boeing expects that it will be ready mid-2023, while Air Force specialists expect it will require “five-to-six software iterations” to fix anticipated performance issues when performing more challenging maneuvers.

This content is imported from youTube. You may be able to find the same content in another format, or you may be able to find more information, at their web site.

This is based on rocky performance already encountered, when the difference between the aircraft’s trajectory and where its nose is pointed (known as ‘angle of attack’) exceeds 25 degrees—a common situation when changing elevation. According to an engineer, when flying slowly at high angles of attack, T-7s exhibited “unexpected airflow across the aircraft, which resulted in undesired wing movement.”

angle of attack diagram for t 7 trainer by gao

GAO illustration of concept of angle of attack, and which flight regimes were observed to cause unexpect movement during T-7 Red Hawk tests.

Government Accountability Office//Wikimedia Commons

Such problems can be corrected for via the flight control software without redesigning the airframe, and the Air Force has already claimed last December that flight control problems “to date have been resolved and will be tested…” But experts consulted by GAO expected new flight control issues to be identified during flight testing, and that each of the expected 5-6 iteration could take six months to complete, potentially delaying production by over two years.

The GAO also complains that Boeing has yet to provide a complete list of materials required to build and maintain each T-7. This is a problem because the Air Force wants to handle as much maintenance as possible in-house to minimize dependence on external contractors, as is notoriously an issue with Lockheed’s F-35 stealth jet.

Currently, the service alleges that Boeing submitted only one-third of the total ‘bill of materials’ three years after it was contractually required. Without that data, the Pentagon doesn’t know what parts it needs, or how much it will cost to sustain T-7s—including the five newer pre-production T-7s Boeing has built.

The report also highlights the “on track but not yet complete” state of the ground-based simulator, specifically related to muddy visuals (apparently not representative of production hardware) and lack of software to interface the simulators with the aircraft (due in mid-2023).

The Boeing-Air Force Relationship

It apparently took 15 months for the Air Force and Boeing to figure out the ejection system problem, due to disagreements on how to measure safety test metrics. The GAO report claims that meeting safety standards will take two more years, going by the current schedule.

Currently, the due date for a production order has been pushed back from 2023 to February of 2025, with expected first delivery following December of 2025 and designation as initial operations capable (IOC) coming no sooner than Spring of 2027. But a delay beyond the date could have cascading financial implications.

rebecca mitchell, t 7a lead flight test engineer, 416th flight test squadron, watches real time flight telemetry of a remote t 7a red hawk test flight from the boeing flight test center in st louis, missouri, at the ridley mission control center on edwards air force base, california, april 30 air force photo by giancarlo casem

Lead Flight Test Engineer Rebecca Mitchell of the 416th Flight Test Squadron based in Edwards Air Force Base, California watches real-time telemetry transmitted by a Boeing T-7 jet over St. Louis Missouri in April 2020.

U.S. Air Force/Giancarlo Casem//Wikimedia Commons

The Air Force is already projected to spend $750 million extending the life of many of its T-38s—an investment which could grow if the T-7 is further delayed. And because the T-38 lacks so many capabilities, trainees end up spending more hours training on expensive combat aircraft that cost much more to fly.

Overall, the GAO report’s biggest beef is that Boeing seems to be operating on an optimistic schedule and assuming a “very high success rate” of forthcoming tests. The watchdog is skeptical that they will keep to that schedule, as there’s now “little to no margin” for delays due to earlier non-satisfactory test results.

Maintenance issues with the aircraft have contributed to the execution of only 42% of planned flight testing. The GAO note that “…the contractor has been able to keep one prototype aircraft flying because it had to borrow parts from the other prototype aircraft.”

The watchdog faults the Air Force for making a risk assessment that failed to factor in risks posed by concurrent development of inter-dependent components (problems with one part causing delay-inducing modifications to other parts) and timely resolution of contractor disputes. Going forward, it advocates a more realistic reassessment of when the T-7 will likely be ready, and establishes conditions under which it would be worthwhile to place a production order even if some parts of development remain incomplete.

The report’s authors are also weary of Boeing’s decision to build the five T-7s at its own expense—before development is finalized and before the Air Force has placed an actual order. Though the decision is intended to reduce delays and costs by beginning early procurement of long lead-time components, the GAO fears it may pressure the Air Force into a premature production order that may eventually require expensive modifications of early production aircraft based on corrections made later in development. However, had Boeing not built the pre-production T-7s, it seems likely delays would be even more serious.

Recently, Air Force secretary Frank Kendall downplayed the benefits of the digital design tools used in the T-7’s development, estimating that they only reduced costs by around 20%. To be fair, that still a considerable savings for expensive warplanes, even if falling short of the earlier boasted paradigm change.

This content is imported from youTube. You may be able to find the same content in another format, or you may be able to find more information, at their web site.

In the big picture, many of the T-7’s problems are likely unavoidable parts of debuting a clean sheet air frame that are bound to be ironed out over time. It looks like digital prototyping, while time-saving, could not avoid the discovery of unexpected problems that hadn’t been simulated in advance, as often occurs in aircraft development.

Perhaps this experience will convince Pentagon procurers to place more value on mature airframes, even if offered at higher prices. However, if the T-7 lives up to its promise, it may still eventually save the U.S. military—and taxpayers—billions of dollars by allowing pilots to complete more of their flight training on simulators, or on a supersonic jet that’s many times cheaper per flight hour than a purpose-built combat aircraft.

It’s just nailing down finishing touches on safe flying that’s proving more costly and time-consuming than expected. Boeing’s cadre of crash test dummies still have their work cut out for them.