November 2012 - Indian Airforce

A
MIG 21 aircraft was cleared for
Ground Run. A few seconds after
engine start up, fuel was found to
be leaking from the starboard side of the
fuselage. The engine was immediately cutoff
and everyone rushed to the aircraft to
find out what had gone wrong.
The STO suggested that the rear fuselage
be removed so that the point of leak could
be located. Soon, a gang started working on
this. Meanwhile, the engine tradesman came
running and told everyone that the ‘L’ shaped
compressor screw driver was missing. This ‘L’
shaped Compressor Screw Driver had screw
driver tips at both the ends of the ‘L’. It was
used by engine tradesman for opening the
engine compressor panels. It was also used
by the radio tradesman to open the radio
panels.
The STO ordered everyone to
immediately deposit their tools so that
the person who had lost the tool could be
identified.
Meanwhile the rear fuselage was
removed but the source of leak could not
be located. Suddenly an engine tradesman
shouted that many compressor blades were
damaged. The airframe i/c found out that
there was a small hole on the starboard side
inner fuselage wall. Flexible fuel tank No 5
was fitted close to that and it was suspected
to be leaking. The STO ordered the removal
of the fuel tank. All of us were surprised
to find a metal part in the fuel tank. It had
pierced into the fuel tank, causing the leak.
The Tool Crib i/c confirmed that one
of the ‘L’ shaped screwdrivers was not
accounted for. One of the tradesmen said
that he had seen the Radio Fitter take the
‘L’ shaped tool from the Engine Fitter’s tool
bag but the Radio Fitter said he had put it
back after sometime. But the doubt was still
lingering.
A Court of Inquiry was ordered.
The findings of the COI were:-
The Radio Fitter had left his tool on the radio
panel and returned the Engine Fitter’s tool to the
tool crib instead of his own.
When a ground run is given on MIG 21 aircraft,
the nose oleo leg gets compressed and the aircraft
stoops (dips) a little in the front due to engine
thrust. Therefore the tool which was left on the
radio panel started moving towards the air intake
(due to vibration) and eventually got sucked into
the engine.
The engine sustained damage due to the FOD
by ingesting a tool. One of the broken pieces of
the tool also pierced the flexible fuel tank causing
the fuel leak.
The Engine Fitter and Radio Fitter were found
to have not checked their tools on completion of
their job. The WO i/c DSS too had added to the
lapse by signing for independent FOD checks
before offering the aircraft for ground run. The
STO did not ensure accounting of tools prior to
start of ground run.
Recommendations by COI:-
Each and every tool is to be serially numbered
by engraving and the serial number of the tool is
to be written in the ‘Tool Crib Daily Issue’ register
against the tradesman drawing that particular
tool.
Since then the practice has continued till date.
Lessons learnt:-
Always count your tools before and
after the ground run.
Own up to the mistakes made by you
rather than hiding them.
Avoid borrowing tools.
- WO PK Swain
INDIAN AIR FORCE 2 0 1 2 N o v e m b e r Aerospace Safety 27