When my buddy Brad was an Aviation Structural Mechanic (2nd Class) stationed at NAS Adak, Alaska, in the mid-1970's he observed the following incident.

 

NAS Adak had a flying club.  The club owned a Beech T-34B "Mentor" trainer.  The T-34 was a Navy training version of the Beechcraft "Bonanza" general aviation aircraft with conventional tail surfaces and fitted with a "bubble" canopy for the instructor pilot and student.  The student and IP sat in tandem (one behind the other) with full controls provided for both.

 

On this particular day, the T-34 had been wheeled onto the flight line after just going through its annual inspection where a newly overhauled engine and propeller were fitted.  One of the club members, a newly arrived Ensign -- or "nuggets" as the most junior flyers in the Navy are called -- had checked-out the plane for a short flight.

 

The Ensign did his normal preflight of the T-34, checking the control surfaces and other external items.  He then mounted-up, strapped himself in, and got ready to start the engine.  Mags to ON.  Primer to RICH.  Engine to START.

 

The starter motor engaged and the prop started its swing -- BANG!  The tow bar attached to the nose gear when flying and the prop ground to a halt with about 6 inches of blade tip removed.  The two bar itself was bent into something resembling a pretzel. 

 

The Nugget shutdown, unstrapped, got out of the plane, and walked to the hangar.

 

Inside, he spotted the Chief Petty Officer in charge and said: "Chief, I'm sorry.  I just broke the T-34."

 

Chief: "You did what, sir?  You'd better show me."

 

The embarrassed flyer took the Chief to the flight line to inspect the damaged bird.  A short time later, the T-34 was wheeled back into the hangar for a new prop and an engine change.

 

When the T-34 was wheeled out to the flight line again, it had a new prop, newly changed engine, and a new brass placard above the starter button.

 

ENSIGN JONES:  REMOVE TOW BAR BEFORE STARTING ENGINE.