Below is formatted like an episode of National Geographic's Seconds from Disaster series.
Before reading, please note that some bits you'll probably already know but will be stated to fit the theme of the show other bits will be added in due to how little info there is to make this episode script.
It's a sunny day in the town of Ponyville as a blue pegasus named Rainbow Dash tears through the skies. Suddenly, while performing her most daring trick called the Sonic Rainboom, the trick sends her through the air and crashing through another ponys' house ceiling. Disasters don't just happen. They're triggered by a chain of critical events. Unlock the clues and count down those final Seconds from Disaster.
Ponyville. A town where ponies come to be with friends and host special events. Every once in a while, they receive a special guest visit from famous ponies like Princess Celestia. 9:00 AM. Rainbow Dash is teaching a friend of hers named Fluttershy the right way to cheer. She's supposed to cheer as loud as she can but unfortunately, her attempts are in vain. Frustrated, Rainbow Dash takes to the skies to practice her act for the Best Young Flier competition. 9:27 AM. With the easy tasks complete, her hardest task is about to take hold. With the speed gathered, Rainbow Dash heads toward the ground but before the trick completes, she loses speed and is catapulted through the air, crashing through the ceiling of her friend Twilight Sparkle's house. Investigators are stunned. How can such an aerodynamic pony designed for high velocity fall short of a trick needing that high velocity? and that had been performed earlier with success?
There's a problem. On a normal aircraft, investigators look for clues in two places called Black Boxes. The Flight Data Recorder gathers information about the aircraft itself while the Cockpit Voice Recorder takes in the last 30 minutes of conversation from pilots before the plane crashes but because Rainbow Dash is not a plane, there's no place to put such heavy metal objects. Making matters worse, only one other bystander was watching that day, her friend Fluttershy. *Fluttershy appears on screen*
"She was moving very fast and I was in complete awe. She made the clouds spin and when she did her Sonic Rainboom, she just stopped a few inches from the ground like there was some innocent creature there she wanted to save, and then she flew through the air and disappeared."
It's a start but it offers no evidence as to what caused Rainbow Dash to crash through the ceiling of Twilight Sparkle's house. Investigators then talked to those that were inside Twilight Sparkle's house at the time Rainbow Dash crashed through. *Pinkie Pie appears on screen*
"She came right through the ceiling and piled us all into the bookcase in Twilight's house"
It looks like Investigators are at a dead end. They review the footage of the event and come up with a theory. Could the air speed at the altitude Rainbow Dash was flying in have affected her speed before she came to a hault? To be sure, they request Rainbow Dash to fly into the sky and try her trick on a windy day. While they find that Rainbow Dash does lose control, the trick is still completed properly. What else could have affected the trick? Upon reviewing the footage from both times the trick had been done, they make their first breakthrough. The 2nd time the trick was performed, Rainbow Dash had both front hooves pointed straight out. It could've allowed the balance needed to complete the trick successfully. They ask Rainbow Dash to perform the trick twice. Once with one hoof pointed straight forward and a 2nd time with both hooves pointed straight forward. When the tricks are complete, the results confirm their suspicions.
Now by rewinding the events of that faithful day, we can reveal what happened to Rainbow Dash's Sonic Rainboom trick. 10 seconds to disaster. Rainbow Dash begins the early stages of her performance for the Best Young Flier competition. 6 seconds left. Rainbow Dash's Sonic Rainboom trick begins but due to her not having both hooves out in front of her, she isn't able to generate a balanced speed through the entire trick and is thrown backward into the air.
After the disaster, Rainbow Dash has successfully performed the Sonic Rainboom at the compeition for the first time since her filly days. For saving the lives of Rarity and the Wonderbolts, Rainbow Dash has been given some time to hang out with her idols of Ponyville.