62-26-06 PIPER: Amdt. 516 Part 507 Federal Register December 8, 1962. Applies to All Models PA-28-150 and PA-28-160 Airplanes With Serial Numbers 28-03, 28-1 through 28-671, 28-678, 28-679, 28-681, 28-685, 28-690, 28-691, 28-693, 28-697, 28-706, and 28-707, Except Those With Exhaust Assembly P/N 63726 Installed.
Compliance required within the next 10 hours' time in service after the effective date of this AD, and each
50 hours' time in service thereafter.
There have been cracks found in the exhaust system on Piper PA-28-150 and PA-28-160 airplanes. As this condition is likely to occur in other airplanes of the same type design, accomplish the following:
(a) Remove carburetor heat muff shroud and conduct a close visual inspection of the complete exhaust system piping for cracks in all welded joints and tubing bends. Pay particular attention to the area near the junction of the cylinder stacks and main exhaust manifold.
(b) If cracks are found, repair by gaswelding. (The exhaust pipe is AISI 321 or 347 corrosion resistant steel.)
(Piper Service Letter 389 covers this same subject.)
This directive effective December 14, 1962.