"Captain? We're gonna need you on this one."
Rainbow Dash loudly sighed. When she was younger, she'd assumed that being Captain of the Wonderbolts was a thrill ride: pushing your envelope, going fast, doing awesome stunts, having the crowd cheer you every step of the way. Now she had come to realize that roughly eighty percent was doing paperwork, setting up org charts, and handling whatever stupid problem had come up this time. (The remaining twenty percent was pretty cool, though.)
So she pushed away from the desk and grouchily trotted after Thunderlane. He was a good XO, even if he was a bit more easily rattled than Soarin' had been. He knew this was Dash's flex time when she could catch up on administrative backlog and wouldn't interrupt without good reason. That just made it more irritating - because 'good reason' usually meant 'above everypony else's pay grade'.
And that part was confirmed when she saw the argument. Two of the Wonderbolt trainers - Misty Fly and Sky Stinger - were loudly yelling at a group of cadets. Unusually, one of the cadets was yelling back. Disturbingly, said cadet was Rainbow Dash.
That was enough to throw Dash for about point-three seconds. (It was, by her count, the seventh time she'd run into an alternate version of herself.) Then she cleared her throat as loudly as possible.
The argument stopped. Both trainers and all the cadets spun to lock eyes on the Captain, and the second Rainbow Dash disappeared in a burst of cyan flame. The cyan changeling left behind looked rather embarrassed when confronted by the real deal.
"Misty, capsule version of what's going on." Dash hoped it would be simple.
Misty Fly snapped a quick salute. "M'am! We were berating this cadet for cheating, m'am!"
"I was not cheating!" the changeling snapped out of turn - and was silenced by Rainbow Dash's furious glare.
"How was he cheating?" The question was aimed directly at Misty.
Taking a moment to clear her throat, Misty tried to keep it short. "He was attempting to use a form other than his own to gain an advantage on the tests, m'am."
Ah. That explained a few things. Dash looked the changeling up and down critically. "Well, at least he picked the right pony to copy since I smashed so many Academy records." The gathered crowd laughed uneasily, not quite sure if it was a joke or not. "What's your name, newbie?"
The changeling's hooves clacked together as he came to attention. "Hyles, m'am!"
"And do you mind telling me why you decided you should do your qualification trials in somepony else's form?"
Hyles locked his eyes straight forward, neck and back rigid. "All Wonderbolt candidates are to give their best efforts, m'am! Included in that is any and all talents, skills, or personal expressions of magic, m'am!"
Dash scratched her chin. "So you're saying being able to change shape is like a pony's cutie mark?"
The changeling hesitated. "I would say it's like a pegasus' ability to stand on clouds. The same for the inherent magics of hippogriffs or griffons." He motioned with his head towards the Dizzitron, where Wonderbolt Reservist Silverstream was helping set up. "Not changing shape to maximize my capabilities would be handicapping myself. M'am."
A familiar cocky grin came to Rainbow Dash's face. Behind her, Thunderlane groaned because he knew that only bad things could happen next. And they did. "See," suggested the captain, "I disagree. But I'll give you a chance to prove me wrong."
"M'am?"
Nightmare visions of more paperwork disappeared as Rainbow Dash's schedule for the next hour suddenly cleared up. "Race me."
Hyles froze up. "What?"
"Race me," repeated Dash. "Show me I'm wrong." She turned and pointed towards Cloudsdale proper. "What we're gonna do is fly over there as a warm-up. You stay in formation with me until we reach the weather factory. Then on my signal, we come back. When we do, I'm gonna go as fast as I can." Her eyes narrowed. "As. Fast. As I. Can."
The changeling swallowed nervously - he knew what that meant.
"Now you're not gonna beat me," Dash continued. "I mean, I'm me, that's not even fair. But you gotta give it your all to keep up. If you can cross the finish line within ten seconds of me, I'll admit you're right and you can use whatever magic you want from here on out. More than ten seconds? Then you admit you cheated. And the Wonderbolts don't take cheaters."
All around, other cadets murmured about the challenge. But Hyles took it with stoic confidence: in a blaze of magic, he transformed back into Rainbow Dash's form and nodded. "Yes m'am."
The journey out to the weather factory was silent - Dash let the cadet stew. It was a relaxing flight for her, but for a rookie (and one who was at least partially not Rainbow Dash) it was nearly a sprint.
She was fine with that. It gave her the opportunity to look back and evaluate him.
Hyles' face was stone-set and stoic, but it wasn't difficult to spot the little tells. Not when he was using Dash's form - she could see the little nervous twitches and tics that she shared. (Her friends had laughingly told her about them quite a few times, usually in the wake of bad poker hands.) He was fretting and worried, and that was good. Dash wasn't really going to kick him out if he lost: she'd made that decision pretty quickly. He truly believed he wasn't cheating, and he had the guts to back up his words. Not a lot of cadets had the courage to take on a challenge like hers without flinching or trying to weasel out of it. Throwing him out of the academy would be a waste.
But she also knew he couldn't keep up on the way back. Not like this.
See, pegasus flight - like that of hippogriffs, griffons, changelings, and pretty much every other intelligent species - was magic. Sure, physical fitness and raw ability accounted for a lot and were what separated the best from the average - but magic is what made it all happen in the first place. It's what made physics take a back seat to awesome.
There had been a series of tests a few years earlier. Quietly conducted by Twilight (of course), she had sought to find out where the limits of changeling magic were. And after quite a few trials, the results were clear: a changeling could assume nearly any form, but those forms were only physical. A changeling in the shape of Princess Celestia couldn't move the sun; one in Starlight Glimmer's couldn't execute obscenely powerful spells; one that looked like Fluttershy couldn't talk to animals; and one that pretended to be Rainbow Dash couldn't do a rainboom.
It was because the change required magic. Quite a lot, in fact. Most of a changeling's inherent magic was tied up in maintaining that form, and it left little to match the feats of other races. Pharynx had gotten the closest, but he'd still fallen short of a rainboom. And since he was as much a changeling's changeling as Dash was a pegasus' pegasus, she was certain noling else could do it either.
To keep up, Hyles would need to do a rainboom. It was possible - Rainbow Dash had personally taught several Wonderbolts how to do it - but he wouldn't be able to while in her form. There just wasn't enough magic to do it.
The question was if he would realize that.
Reaching the weather factory, Dash made the turn. It had been agreed they would each dip a hoof into the liquid rainbow pool as evidence they hadn't turned back early. She just barely grazed the pool with a hooftip before completing the turn. It was a straight shot back - and it only took a tenth of a second before she was off.
Rainbow didn't hit top speed immediately - doing that inside the weather factory would cause huge damage and she was still in the bad books from the whole hibernation debacle. But as soon as she was clear?
BOOM.
The world burned with bright light as physics took a back seat to awesome. But Dash lied again: she didn't keep accelerating. Instead of going as fast as she could, she dropped to a cruise - still faster than the boom behind her, but at a comfortable pace. It would give him a chance and give her the opportunity to observe.
Hyles was struggling. He was fast - obviously. He had to be to make it as far into the Wonderbolts as he had. But he wasn't Rainbow Dash fast, even when he was Rainbow Dash. His wings were pumping furiously, body straining with effort. She could see the air pressure building up like a wall against him - the wall that separated 'fast' from 'boom'. He wouldn't be able to push through it. She knew that he couldn't.
Not that he wasn't trying. Frothy sweat was building up on his flanks as he struggled against physics. That he was even getting so close was a little impressive.
Rainbow Dash barely registered that she crossed the finish line. Her wings automatically tilted, letting her bank around to bleed off speed and get a better view as Hyles struggled in vain.
With the angle, she could see him hit the ragged edge of flight and start to destabilize. The bow shock behind him - the disruption of the air in his wake - was becoming unmanageable as the turbulence got stronger and stronger. He had about two seconds to break through the wall before he lost control and crashed out.
Not that there was any shame in crashing out - for every Wonderbolt who had managed to break through, there were five that couldn't make it. And even the ones that succeeded had built that on top of dozens of failures.
Dash's bank hit the furthest point and she started looping back towards the landing strip. Her momentum was dropping - his was holding steady. She'd arrive about ten seconds after he had initially passed the line, and she was going to beat him back. Disappointing.
He had another second. Maybe. Hyles was struggling to keep his wings straight, but that just made the problem worse. Rather than powering forward to break through, he was spending his power and momentum on adjustments kept him in the danger zone.
Just as she was bracing for him to crash, Hyles surprised Rainbow Dash. A burst of teal fire washed over him, filling the wildly turbulent air behind him with flames. He came out the other side in his natural form, gossamer wings buzzing faster than the eye could track.
Dash's breath hitched in anticipation as she saw the air bend around Hyles' outstretched hooves. His energy freed up from taking Dash's form pushed him just that little bit harder against the wall and–
BOOM.
The sky cascaded with a grayscale shockwave. A bit in the back of Rainbow Dash's head made idle note to train up a griffon and see if other non-pony races had different colored rainbooms. The rest of her, however, was busy fighting the urge to cheer. She didn't want to risk distracting the cadet as he flew faster than any changeling before him.
They reached the finish line at almost the same time - she landed into a comfortable, casual trot; he plowed into the clouds, leaving behind a shallow trench.
Laying in the ground, Hyles gasped for air. Even a non-changeling could see the wild mix of emotions rattling around his head: exhaustion and excitement and disbelief and ecstasy.
Rainbow Dash, on the other hoof, trotted over to Misty Fly and looked at her stopwatch. It clearly read 10.14 seconds, but that wouldn't do. Dash raised her head and made her announcement. "Nine point seven-four seconds behind me."
The crowd - cadet and Wonderbolt alike - erupted into cheers.
Misty traded nods with her captain, sealing the knowledge that only they knew the true time and that it would never be spoken.
Grabbing a water bottle from the bench, Rainbow Dash brought it over to the collapsed, panting changeling. Holding it out, she grinned at the cadet. "So," she asked, "What did we learn?"