Transcript IMP - Sea King Symposium

IMP AEROSPACE
Sea King Pylon Repair and Overhaul
by
Anick Chiasson
Intermediate Aero/Mechanical Engineer
Rotary Wing Engineering
IMP AEROSPACE
IMP Aerospace, P.O. Box 970, Enfield, Nova Scotia, Canada B2T 1L5
Tel. 902. 873.2250 • Fax 902 873 2290 • e-mail. [email protected]
Website. www.impaerospaceanddefence.com
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Presentation Outline
• Introduction
• Overview of the Pylon
• Areas of Interest on the Pylon
• Engineering Process
• Area 1: Tail Gearbox (TGB) Support Fitting
• Area 2: Pylon Fold Fitting
• Area 3: Oversized Rivets on left side of a Pylon
• Area 4: Hinge fittings
• Area 5: Oversized Fasteners at Hinge Fittings
• Questions
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Introduction of IMP Group Ltd.
Number of
professionals
IMP Group
Ltd.
IMP AEROSPACE &
DEFENCE
IMP AEROSPACE
Engineering Branch
Aeronautical
Support
Engineering
Rotary Wing
Engineering
= 22
Fixed Wing
Engineering
= 26
Specialty
Engineering
= 12
= 32
Integrated Logistics
Support (ILS)
= 29
Technical
Publications
= 30
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Overview of the Pylon
Pylon
The Pylon is the tail end of the aircraft.
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Overview of the Pylon
• The Pylon holds the Tail Rotor and the Stablilizer.
• The Intermediate Gearbox (IGB) and the Tail
Gearbox (TGB) are installed on the Pylon.
• The Pylon is under intense load (torsion and
bending).
• The Pylon is a critical primary component of the
Sea King.
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Areas of Interest on the Pylon
Area 1
Area 3
Area 2
Area 4
Area 5
•
Area 1: TGB Support Fitting
•
Area 4: Hinge Fittings
•
Area 2: Pylon Fold Fitting
•
•
Area 3: Row of oversized
Rivets along LH side
Area 5: Oversized Fasteners
at Hinge Fittings
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Engineering Process
•
Sea King part or component is inducted in our facility.
•
The damage is assessed.
•
Production department requests Engineering services for a
serviceability assessment.
•
Engineering team calculates safe limits for rework/repair.
•
Engineering team prepares a detailed repair scheme document.
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Area 1 : TGB Support Fitting
Mounting
Pads and
Bolt Holes
Barrel
Nut Holes
•
Damage found inside barrel nut bore holes and bolt holes
•
Damage found on Tail Gearbox (TGB) mounting pads
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Area 2: Pylon Fold Fitting
The power fold system was added to the Canadian
version of the Sea King.
Pylon
Fold
Fitting
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Area 3: Oversized Rivets on left side of a Pylon
Rivet #55
FWD
UP
Rivet #1
Row of oversized Rivets (Quantity 55) was discovered at overhaul.
The rivets found were 1/4” and the OEM design was 3/16”.
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Area 4: Hinge Fittings
Upper Hinge Fitting
(Top View)
Lugs
• The lugs are two of the
attachment points to the
aircraft fuselage.
• The four mounting pads
are to install the
Intermediate Gear Box.
IGB
Mounting
Pads
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Area 5: Oversized Fasteners at Hinge Fittings
Upper Hinge
Fitting
Hi-Lok fasteners qty 11
on either side at upper
hinge fitting
UP
FWD
Hi-Lok fasteners qty 8
on either side at lower
hinge fitting
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Area 5: Oversized Fasteners at Hinge Fittings
Initial Problems:
• 11 pylons with oversized fasteners at installation of Upper and
Lower Hinge Fittings.
• No approved documentations were found to substantiate the
oversized fasteners.
• Up to 0.292” from their original design size of 0.188”.
• Biggest problem was the lack of acceptable edge distance (ED)
on the different structure parts.
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Area 5: Oversized Fasteners at Hinge Fittings
Assessment:
Option 1
Repairing the pylon by replacing
the structure affected; and
revert to 3/16” fasteners:
Option 2
Analyzing the damage for
serviceability:
• The margins of safety of the
• 400 man-hours per pylon
• Lead time to get parts
• Material cost
• Manufacturing hours to
manufacture parts needed
Fittings were high
• The skin, cap angles and
doubler had to be analyzed
• The analyses would render
at least 8 pylons serviceable
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Area 5: Oversized Fasteners at Hinge Fittings
Example of the multiple layers
within the Pylon.
Plugging the oversized holes
was required for this repair.
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Area 5: Oversized Fasteners at Hinge Fittings
Results:
• Engineering was able to analyze the structure with
the oversized fasteners.
• Those completed and approved analyses rendered
6 pylons serviceable.
• More pylons will be deemed serviceable using the
completed analyses.
• Fatigue limits in terms of life span for each pylon
were achieved.
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Area 5: Oversized Fasteners at Hinge Fittings
Edge Distance
(ED) less than 2D
Splice cut line
Example of spliced skin (above)
Example of less than 2D edge distance (left)
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Questions
Thank you for the opportunity to highlight IMP’s
Pylon R&O capabilities!
Please come see a Pylon at our booth to discuss any
further questions that you may have!
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