It’s hard to sustain success at a service academy.

Air Force set a standard for doing so during the tenure of coach Fisher DeBerry (1984 to 2006), posting winning records in 16 of 19 seasons. However, there were a few slipups along the way, such as a 5-7 mark in 1988 sandwiched between 9-4 and 8-4 campaigns.

Navy’s rise to prominence among the service academies coincided with a down period for Air Force, which endured losing records in each of DeBerry’s last three seasons.

Troy Calhoun returned the Falcons to prominence by directing five straight winning seasons, but a slight step back in 2012 (6-7) turned into a 2-10 disaster in 2013.

This year, Air Force has 10 wins for the third time under Calhoun, having rebounded from back-to-back 5-7 marks.

Navy has been the most consistent service academy football program since 2003, notching winning records in 15 of the last 17 seasons. However, the Midshipmen have not been immune to the occasional slip, going 5-7 in 2011 and then enduring a 3-10 debacle a year ago.

Jeff Monken was an assistant at Navy under head coach Paul Johnson, who was responsible for transforming the program. Following a three-year stretch that saw the Midshipmen go 3-30, Johnson directed a turnaround that produced eight straight winning seasons, highlighted by a 10-2 record in 2004 and 10-4 in 2009.

Monken basically replicated at Army West Point what Johnson did at Navy. Monken took over a downtrodden program that suffered losing records in 18 of 19 years and completely turned it around.

Army went 29-10 from 2016 through 2018, culminating with a school-record 11 wins a year ago. Monken has learned the hard way what DeBerry, Calhoun and Navy coach Ken Niumatalolo already knew: Down years are almost inevitable at service academies, where there’s always a fine line between winning and losing.

Army (5-7) is assured of its first losing season since finishing 2-10 in 2015 and enters Saturday’s showdown with archrival Navy hoping to salvage one last goal. If the Black Knights beat the Midshipmen, they would retain the Commander-in-Chief’s Trophy since there will have been a three-way tie among the service academies.

“It’s been really frustrating,” Monken said. “When you’ve had success and you let things slip, it’s disappointing and discouraging. Ultimately, I’m responsible for it, so I have to look in the mirror and figure out what went wrong.”

Monken knows some of the reasons, starting with the departure of a large senior class that was part of rebuilding Army football. Standout players such as center Bryce Holland, fullback Andy Davidson, slotback Darnell Woolfolk and linebackers Kenny Brinson and James Nachtigal played prominent roles in the three straight winning seasons that produced consecutive Commander-in-Chief’s Trophy championships.

“When they walked out the door, you lose a lot more than you realize,” Monken said. “It’s hard to replace the intangible things like experience and leadership.”

Despite the losses, Army came into this season riding the momentum that comes with compiling an 11-2 record capped by a blowout victory over Houston in the Armed Forces Bowl.

“We started out with a team that was very confident and excited about the upcoming season,” Monken said. “We had a great win to open the season in a really tough, physical game against Rice. That reinforced the collective confidence.”

Army traveled to Michigan Stadium truly believing it could take down one of the blue bloods of college football. After all, in 2018, it had nearly knocked off fifth-ranked Oklahoma on its home field, falling 28-21.

Sure enough, Army almost pulled off the upset, pushing then-No. 7 Michigan into overtime before succumbing 24-21.

“Losing that game … took something away from our psyche,” Monken said. “ Our players really had their sights set on that game. When we didn’t win, it was somewhat of a letdown.”

Standout senior Kelvin Hopkins, who became the first Army quarterback to throw and pass for 1,000 yards in the same season, got injured during the Michigan game. He sat out the next two games, which were wins at Texas-San Antonio and home versus Morgan State.

Hopkins returned against Tulane and rushed for 132 yards and two touchdowns in a 42-33 loss that snapped Army’s 15-game winning streak at Michie Stadium. Failing to protect the hallowed home turf for the first time in almost three seasons was another mental blow.

Thus began the five-game losing streak that would prove the undoing of Army’s season. That stretch culminated with a 17-13 loss at Air Force, which came up with a huge defensive stand in the red zone during the final minute. Facing fourth-and-goal from the 6-yard line, backup quarterback Jabari Laws threw an incomplete pass into the end zone with 33 seconds left.

That was one of five games the Black Knights lost by one score or less. In the previous three seasons, Army boasted a 14-5 record in contests decided by one score or less.

“We couldn’t get those close games to swing in our direction,” Monken said. “A lot of times the ball just doesn’t bounce your way.

“When you get into those one-score games and things don’t go your way, it tests your character. When you need to dig deep to make that key play, if there is something a little off, it shows through. It’s hard to put your finger on it.”

Injuries have hampered Army, which was young and inexperienced coming into the season. Monken said the Black Knights had four offensive linemen make their first career start against Air Force.

“That’s been a theme at a lot of positions,” Monken said. “At one point a few weeks ago, I looked out on the field and saw we had 10 starters out with an injury.

“In academy football, the teams that win are filled with veterans who have developed and grown up. We didn’t have enough of those players this season.”

Not having Hopkins at 100% for most of the season certainly hasn’t helped. The 5-foot-10, 205-pounder is a dynamic performer who was named MVP of both the Army-Navy game and the Armed Forces Bowl in 2018.

Laws, a sophomore, has been joined by junior Christian Anderson and freshman Jemel Jones in playing quarterback for the Black Knights at some point this season.

“Rotating quarterbacks hasn’t been the reason we haven’t won,” Monken said. “That said, playing a bunch of different guys at that important position is not ideal.”

Army’s upward trajectory from 2016 through 2018 has made this season’s sudden free fall somewhat stunning for everyone involved with the program.

“It’s hard to go through that, especially with a team that’s experienced so much success and came in with such high hopes,” Monken said. “I’m proud of the way our guys have battled. We’ve played with great effort and stayed in every game.”

Senior cornerback Elijah Riley seconds that assessment, adding that Army’s record has been the perfect storm of factors that turned last year’s wins into this year’s losses.

“This season isn’t really that much different than last season, except for the results,” he said. “We’ve played hard, [but] we just haven’t been on the winning side of as many games.

“It’s tough because all the expectations we had for ourselves as a senior class have not been realized. At the same time, it’s been a great learning process. Injuries have forced a lot of younger guys to step up and that’s a positive because those guys will be better because of that experience.”