INTERNATIONAL HELICOPTER SYMPOSIUM 2005

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• INTERNATIONAL HELICOPTER SYMPOSIUM 2005

MONTREAL, QUEBEC CANADA SEPTEMBER 27-29, 2005
Gary Souza Chief Project Engineer Model
250 Helicopters Small Gas Turbines Rolls-Royce
Corporation
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THE INFLUENCE OF ENGINE MAINTENANCE AND OVERHAUL
ON ROTORCRAFT SAFETY
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ROLLS-ROYCE MODEL 250 SAFETY RISK ASSESSMENT -
CAUSE ANALYSIS

• Understanding of future safety event rates and
  associated risks can
• be gained by assessment of past fleet events and
  their causes

Event Severity Historical Rates
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U.S. HELICOPTER ACCIDENT SUMMARY STATISTICS -
1996 -2004
Source HAI Accident Summary
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MODEL 250 SAFETY RISK ASSESSMENT
Event Break-down of 1561 Events in Study Period
Average No. of Engine-Involved Events per Year
(1996-2004)Does not include Potential Hazards
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MODEL 250 SAFETY RISK ASSESSMENT General Causes
of 234 Engine-Involved Events during Study Period
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MODEL 250 SAFETY RISK ASSESSMENT MODEL 250
POWER LOSS MODES ALL MODELS
Fatigue
Misalignment
Wear
TOP 15 MODES ACCOUNT FOR 56 OF POWER LOSS EVENTS
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REVIEW OF KEY MAINTENANCE INVOLVED EVENTS
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FUEL CONTAMINATION
Failure to Properly Maintain and Inspect Fuel
System Results In
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FUEL CONTAMINATION

• Fuel system contamination with the use of Jet A
  fuel and anti-icing inhibitor, Diethylene Glycol
  Monomethyl Ether (DIEGME).
• DIEGME inhibitor draws water molecules from the
  fuel and over time forms an organic gel-like
  substance (coined Apple Jelly) in the bottom of
  fuel tanks.
• When this gel-like material is detected in the
  aircraft fuel system or fuel storage tanks,
  inspection of the entire engine fuel system is
  required.
• Inspect airframe / engine mounted fuel filters.
• Separate, inspect / clean the fuel nozzle inlet
  screen
• The formation of this gel-like material may
  result from
• Improperly maintained fuel storage tanks
• Improper additive injection method or ratio

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FUEL CONTAMINATION
FUEL SYSTEM CONTAMINATION WITH DIEGME
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FUEL CONTAMINATION
FUEL STORAGE TANK CONTAMINATION WITH DIEGME
(Apple Jelly)
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FUEL CONTAMINATION

• FUEL SYSTEM CONTAMINATION CAN RESULT IN
  RESTRICTED FUEL FLOW, CAUSING
• ENGINE STARTING STAGNATION
• HUNG START OR VERY COOL, LONG START
• ENGINE POWER LIMITING
• INABILITY TO MAINTAIN Nr AT REQUIRED SETTING
  UNDER LOAD RESULTING IN Nr DROOP
• IN-FLIGHT POWER LOSS
• ENGINE FLAME-OUT OR CUT-BACK

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FUEL CONTAMINATION
CLEAN FUEL NOZZLE INLET SCREEN
DIRTY FUEL NOZZLE INLET SCREEN
Nozzle Separated for Cleaning
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FUEL CONTAMINATION
Collapsed contaminated screen resulting in loss
of power in-flight
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COMPRESSOREROSION CORROSION
Failure to Inspect Compressor Cases and Blades
Regularly for Erosion and/or Corrosion Results In
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COMPRESSOR CORROSION EROSION INSPECTIONS
COMPRESSOR FAILURE
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COMPRESSOR CORROSION EROSION INSPECTIONS
COMPRESSOR BLADE FAILURE
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COMPRESSOR CORROSION EROSION INSPECTIONS

• Inspect Compressor Cases and Blades Regularly for
  Erosion and/or Corrosion
• Minimum 300 Hours When Operating in Erosion
  and/or Corrosive Environment
• As Required in Moderate Environments
• Never Greater than Manufacturers Recommendation.

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COMPRESSOR CORROSION EROSION INSPECTIONS
COMPRESSOR CASE EROSION
EXPOSED VANE BAND IS NOT ACCEPTABLE
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COMPRESSOR CORROSION EROSION INSPECTIONS
COMPRESSOR VANE EROSION
NOTE EROSION UNDERCUT NEAR VANE ROOT AT PLASTIC
LINE
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COMPRESSOR CORROSION EROSION INSPECTIONS
COMPRESSOR BLADE FAILURE
NOTE PITS AT ROOT AREA OF BLADE
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SERIES II COMPRESSOR CORROSION EROSION
INSPECTIONS
CRACK FORMING ON LEADING EDGE NEAR ROOT FROM
CORROSION PIT
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ENGINE GAS PATH CONTAMINATION
Failure to Regularly Remove Gas Path Contaminants
Results In
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TURBINE WHEEL HOT CORROSION FAILURE

• TYPICAL MODEL 250 1ST STAGE TURBINE WHEEL HOT
  CORROSION
• TYPICAL APPEARANCE AFTER IFSD EVENT
• CORROSION DAMAGE REDUCES AIRFOIL CROSS-SECTIONAL
  AREA
• BLADES FAIL IN OVERLOAD

98FA8-026
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Proper Contamination Removal (water rinse)
Instructions Using Water Only
250-C18 CSL-141 250-C40 CSL-5017 250-C20
CSL-1135 250-C47 CSL-6004 250-C28
CSL-2082 250-C30 CSL-3085 250-C20R CSL-4018 The
above CSL has been revised to remind operators
the importance of doing a daily water rinse to
all Rolls-Royce Model 250 Series engines that are
flown in a corrosive environment WARNING FAILURE
TO PROPERLY FOLLOW THE WATER RINSE PROCEDURES
COULD RESULT IN CORROSIVE ATTACK AND ENGINE
FAILURE WARNING SALT LADEN HUMIDITY AND
CHEMICALS WILL CORRODE THE ENGINE AND COULD CAUSE
IT TO FAIL. The highest quality of water must be
used. Distilled or demineralized water is
recommended
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TURBINE WHEEL HOT CORROSION

• RECENTLY PUBLISHED REVISIONS
• CSL141 PUBLISHED REQUIRING DE-MINERALIZED WATER
  FOR RINSE / WASH
• CSL 205 PUBLISHED TO INSPECT FOR HOT CORROSION
  (SULFIDATION) OF 1ST STAGE TURBINE BLADES
• REQUIRES 600 HR INSPECTION OF THE 1ST STAGE
  TURBINE BLADES FOR OPERATORS WHO ARE EXPOSED TO
  CONDITIONS WHICH PROMOTE HOT CORROSION
• SAME AS COMPRESSOR INSPECTION
• REQUIRES OPERATORS WHO DO NOT USE DE-MINERALIZED
  WATER OR ARE UNSURE OF LEVEL OF MINERAL CONTENT
  OF WATER USED FOR COMPRESSOR RINSE / WASH TO
  PERFORM 600 HR INSPECTION OF THE 1ST STAGE
  TURBINE BLADES

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MAINTENANCE OF FUEL, LUBE AND PNEUMATIC SYSTEM
LINES
Failure to Properly Maintain and Inspect Fuel,
Lube and Pneumatic System Lines Results In
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MAINTNENANCE OF FUEL, OIL AND AIR
LINESMAINTENANCE WARNING CONTROL SYSTEM
PLUMBING
250-C18 CSL A-169 250-C20 CSL A-1166 250-C20R
CSL A-4036 250-C28 CSL A-2113 250-C30 CSL
A-3117 The above CSL has been issued to remind
operators of the importance of proper alignment,
clamping and torqueing of engine Control System
Plumbing
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MAINTENANCE OF FUEL, OIL AND AIR LINES
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MAINTENANCE OF FUEL, OIL AND AIR LINES
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SUMMARY

• Improper Engine Maintenance and Overhaul Affects
  Safety
• Proper Maintenance in Accordance with
  Manufacturers Recommendations is Essential to
  the Safety of Engines Installed in Rotorcraft

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THANK YOU!QUESTIONS?