"The wing!" Frank cried out.  "It's breaking up!"

Simultaneously the Hardys and Chet were flung against their seat belts.  The engine screamed.  The plane plunged into a downward spiral.  After four turns, the gyrations tightened into a spin.

"We must be losing nearly a fourth of our lift on the left wing!" Jack shouted.  "Our aileron is almost useless!"

He chopped engine power, shoved full right rudder, and snapped the stick forward.  Recovery was slow, but Jack finally maneuvered the plane back to straight and level.

Looking out, the boys saw the damaged wing section still attached.  But jagged ribbons of metal were trailing from its lower surface.

"Will we make the airport?" Joe asked.

Jack stared tensely ahead, then glanced back.  "We've already stretched our luck, but if we take it slow, we should make it.  Don't move around!"

Carefully he guided the craft back to the outskirts of Bayport.  Chet, his face white, crouched next to Joe with his fingers crossed.  "M-me and m-my big hobbies!" he groaned.

In silence Jack maneuvered the plane skillfully out over Barmet Bay.  Descending, he banked west toward the airport.  Minutes later, he brought the craft to a safe landing.  Relieved, everyone climbed out.

Jack and the boys looked at the damaged wing.  The pilot frowned.  "I don't understand how it could've happened."

The outer section of the wing hung slightly awry from an uneven breach in the metal.  Aghast, Joe spotted several dents around the cut.

"This was no accident - the wing was slashed!"

Jack grimly affirmed Joe's suspicion of sabotage.  "One clean blow - clean enough for us not to notice it before taking off.  The wind did the rest.  It could have been an ax -"

"Or a machete!" Frank broke in.  "That green sedan behind us on the way here - maybe those vandals were tailing us, and did this job."

"For revenge!" Chet said, rolling his eyes in fear.

Frank disagreed.  "That's a pretty strong dose of revenge coming from vandals - unless they aren't just vandals."