"The Last Crash of the Sunchaser!" is the twenty-second episode of the animated series, DuckTales.
Stuck on a precarious peak, the kids secretly search the plane for clues about Della's disappearance.
The family heads to Monacrow for a vacation while Donald Duck decides to stay home to continue fixing the houseboat, claiming he was almost finished repairing it. On their way, the kids recover shredded pieces of documents from the McDuck archives on Della Duck and the "Spear of Selene", and try putting the documents back together before Scrooge McDuck can find it. However, Scrooge, while flying the plane, crashes the Sunchaser into a peak, and one of the pieces slip away during turbulence. Unable to lift without damaging the engines, the airplane can't fly them off it, leaving the group suspended on top. Bentina Beakley then chides Scrooge for putting the kids in danger.
Noticing the piece slipped into the jeep's window, the kids distract Scrooge and Beakley while Dewey reaches for the piece. Launchpad McQuack misheard them and drives the jeep towards the other side of the Sun Chaser, causing the airplane to tilt towards the side and the plane door to open with Launchpad at the edge of it. Beakley gets the kids to the other side while Scrooge rescues Launchpad, but Scrooge orders the kids to stay in their seats for balance. Launchpad entertains the kids with a tape of Darkwing Duck stuck on the credits theme due to the crash until they can figure a solution. Scrooge confidently attempts to fix the plane against Beakley's concerns for the kids until Beakley pleads with Scrooge to admit he can't fix everything, leading Scrooge to instinctively say that nothing bad will happen to "her" before correcting himself.
Meanwhile, Dewey tries to retrieve the piece from the cockpit. Huey moves to the other side to counterbalance the plane as Webby coordinates the two in the right direction. Right when Dewey retrieves the piece, however, he is spotted by Scrooge and Beakley. Scrooge then demands Dewey give him the paper but it is blown away so Dewey chases after it into the cargo, and followed by Scrooge, where the added weight tips the plane to their side. Dewey then rushes to the piece where it has now flown out through the side window, and climbs on top of the plane once he realizes it is caught inside the right propeller. Dewey reaches for the piece with Scrooge close by trying to save him, but Dewey will only come back with him if he tells him the truth about the Spear of Selene.
Scrooge then reveals the whole story: ten years ago, he, Donald, and Della were seasoned adventurers who had visited just about every possible location on the globe. Before the triplets hatched, Della wanted to embark on a journey to a new frontier — outer space. Donald thought the trip would be too risky with Della's sons about to hatch, and while the two argued about it for days, Scrooge built the rocket dubbed the Spear of Selene so he could reveal it to Della as a surprise when the triplets were born. Della, however, took the rocket on a test run before Scrooge could surprise her, and the photo of this event is on the very piece Dewey was retrieving. Della then braved into an unexpected cosmic storm, but despite her confidence and Scrooge's assistance through the radio, she was struck by a lightning bolt and stranded in space. Heartbroken, the boys accuse Scrooge of leading Della into that storm, leading Scrooge to become frustrated with everyone while the Sun Chaser falls from the peak. Thankfully, the fall isn't too high and everyone on the plane survives, though Launchpad successfully crashes it a bit.
At the manor, Donald has successfully rebuilt the houseboat and sees the bitter triplets who inform him they learned the truth, and solemnly prepare to leave the manor. Webby, Beakley, and Duckworth take a vacation away from Scrooge who is scolded by Beakley before leaving. Now alone again, Scrooge, reminiscing his countless efforts and failures in trying to find Della while the other's accusations echo in his mind, coldly states he is happy this way, though his tears suggest otherwise.
As of this episode, six months have passed since the events of "Woo-oo!"
In the scene where Mrs. Beakley sticks a knife into the floor of the cargo hold to prevent the crate from sliding, the knife she uses is a balisong or bufferfly knife, a kind of pocket knife from the Philippines.
The scene in which Scrooge sits in an armchair in the dark is based on the panel drawn by Carl Barks in which Scrooge McDuck first appeared.
Clips from the episode are shown in Disney Channel's Animation Cram Session promo.
According to Huey, Webby, and Launchpad Monacrow has "experimental racecars, lasers, and airplanes". This is a clear reference to the theme song.