I can't understand why they'd specify liquid penetrant NDI. It can't
reliably find small cracks, and is easy to mis-use (with subsequent
false security that the part is not cracked). I'd go for eddy current
or ultrasound, myself. If you do use penetrant, make sure you follow
the directions precisely.

-John

On Apr 6, 4:52 pm, Burt Compton - Marfa wrote:
Information alert -- USA.
FAA Airworthiness Directive 2010-08-01 for Blanik L-23 sailplanes.

Cracks have been reported in 7 Blanik L-23 elevator / stabilizer
"inner" hinges by EASA (Europe.)

Inspection per the Blanik Mandatory Inspection Bulletin # L-23/052a
(dated March 2, 2010) for cracks must be accomplished by disassembly
and reassembly of the elevator from the stabilizer by an Airframe
mechanic and a logbook entry is required for compliance.

Appears that non-destructive / liquid or dye-penetrant inspection for
cracks must be accomplished per Mandatory Bulletin paragraphs A1, A2,
A4.

If not acomplished, your L-23 is grounded after April 26, 2010. .

For EASA (Europe) this will be a recurring AD, every 1,000 hours. FAA
has not set hours yet for repetitive inspections. Expect an amended
AD from FAA on repetitive inspections in the near future, as FAA may
determine the hours of Time In Service if more cracks are found during
this mandatory inspection of elevator hinges. There is a short
public comment period ending May 21, 2010.

Read and print this AD he http://edocket.access.gpo.gov/2010/2010-7591.htm

Read and print the Blanik Mandatory Inspection Bulletin # L-23/052a
referenced in the FAA AD he http://www.let.cz/files//bulletines/...23_English.pdf

Read the AD yourself, comply by April 26, 2010 and do not rely on this
message for guidance. This message is just an information alert to
fellow US Blanik L-23 owners.

Burt
Marfa, Texas USA