us army aviation helicopter dynamic componentsapache rotor systems zone l – 37.4% of pitch...
TRANSCRIPT
October 26, 2009Presented by:
Dr. Robert VaughanChief Technology Branch
Structures & Materials DivisionAviation Engineering Directorate
Aviation and Missile Research, Development and Engineering Center
Presented to:DoD Maintenance Symposium
“Understanding and Combating Aging”Phoenix Convention Center, Phoenix, AZ
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US Army Aviation Helicopter Dynamic Components
Approved for public release; distribution unlimited. Review completed by the AMRDEC Public Affairs Office (10/09/09 and FN4254 ).
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CRACKED H-47 SWASHPLATE ROTATING RING
In 2004 routine maintenance discovered a MH-47E Forward Rotating Ring with fatigue cracks during overhaul. This was a first time anomaly. Subsequent inspections have found that ~15% of the Swashplates inspected have these micro cracks near the bearing surface.
Testing, Analysis, and Inspections used to minimize the risk associated with fatigue cracking in the swashplate.
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AH-64D Tail Rotor Scissors Assembly Fatigue Failures
On 30 May 2009, failure of both drive link scissors on AH-64D Apache Aircraft xxx occurred during operational usage.
On 2 Jun 2009, a single knuckle lug of a single TR drive link scissors failed on AH-64D Apache Aircraft xxx during operational usage .
On 8 Jun 2009, a single lug of a single TR drive link scissors failed at the swashplate interface on AH-64D Apache Aircraft xxx during operational usage.
Failure
Failure
Failure
Failure Three failures of the TR drive links were discovered this spring.
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Erosion of Engine Compressors
• T700 Engine Stage 1 Blisk Erosion– Erosion is caused by continuous
ingestion of small hard particles such as sand into engine
– Erosion degrades compressor efficiency and leads to reduced engine performance
RIMFIRE inspection at Corpus Christi Army Depot
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Compressor Erosion Trending
Percentage of Engine/Module Removals Due to Compressor Erosion
T700 Series Engines
From RIMFIRE Database
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Stage 1 Turbine Nozzle Vane Conditions
RIMFIRE inspections at CorpusChristi Army Depot
T700 Engine – 1ST Stage Turbine Nozzle Vanes- Oxidation, Burns and Cracks- Increased Temperature/Performance Criteria
Accelerates Condition Degradation
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Stage 1 Turbine Nozzle Vanes Trending
Percentage of Engine Removals Due toBurns, Oxidation and Cracks of Stage 1Turbine Nozzles
Removal Date
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Stage 1 Turbine Blade Conditions
RIMFIRE inspections at CorpusChristi Army Depot
T700 Engine – 1ST Stage Turbine Blades- Oxidation, Burns and Cracks- Increased Temperature/Performance Criteria
Accelerates Condition Degradation
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Stage 1 Turbine Blade Trending
Percentage of Engine Removals Due to Burns, Oxidation and Cracks of Stage 1Turbine Blades
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Chinook Rotor Systems
Zone J – OD Outside of Limits
– 34.7% rejected due to this condition
Hinge Pin Analysis
RIMFIRE Reports
Zone J
DMWR Limit = 4.5090 inches min.
Average = .0102” under limit
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Chinook Rotor Systems
• 294 Hinge Pins Inspected in RIMFIRE Project
• 121 Rejected by CCAD• 41.2% Reject Rate
Hinge Pin Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.
Reasons for Rejection Frequency *
1 Zone J - OD Out of Limits 102
2 Zone H - OD Out of Limits 6
3 Zone B - Scoring 4
4 Zone D - Nicks/Wear 3
5 Zone D - Stained 2
6 Misc. Conditions 7
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Black Hawk Rotor Systems
• Zones A & R Damage– 14% of Shafts rejected due to
Chipping/Gouging/Denting in these Zones
RIMFIRE Reports
Zone R
Zone A
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Black Hawk Rotor Systems
• 150 Shaft Extensions Inspected in RIMFIRE Project
• 21 Rejected by CCAD• 14% Reject Rate
Main Shaft Extension Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.
Reasons for Rejection Frequency *1 Zone R Damage 122 Zone T Damage 73 Zone A - Spline Damage & Wear 44 Zone H - Chipped 15 Zone P - Chipped 1
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Apache Rotor Systems
Zone L
– 37.4% of Pitch Housings did not pass initial DMWR inspection due to incorrect bonding prep.
Pitch Housing Analysis
RIMFIRE Reports
Zone L
This is a repairable condition per DMWR
Zone K
– 32.8% of washers in this zone were debonded and did not pass initial DMWR inspection.
– 24.6% of washers in this zone were missing and did not pass initial DMWR inspection.
Zone K
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Apache Rotor Systems
• 329 Pitch Housings Inspected in RIMFIRE Project
• 191 Failed Initial DMWR Inspection Criteria
• 58.1% Reject Rate†
• All -15 Pitch Housings with over 300 hours are being Retired at Depot due to 1204 Hour Life Limit.
Pitch Housing Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.† Prior to any repairs
1 Zone L - Bonding Prep Incorrect2 Zone K - Debonded3 Zone K - Missing Washers4 Zone C Bushing Wear5 Zone F Bushing Wear6 Zone E Liner & Shim Debonding/Wear7 Zone G Bushing Wear8 Zone A Bushing Wear9 Dents & Gouges10 Scored/Scratched
Data collected between 2/5/2005 and 7/16/2007
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Apache Rotor Systems
Zone C - Wear
– 15.5% of Pitch Housings failed initial DMWR inspection due to inner diameter wear of bushing exceeding max. limit.
Pitch Housing Analysis
RIMFIRE Reports
DMWR Limit = 2.507 in. maxMean Wear = 0.0028 over limit
This is a repairable location.
Zone CFr
eque
ncy
0.0090.0060.0030.000-0.003
10
8
6
4
2
0
Mean 0.002825StDev 0.002807N 36
Normal Histogram of Zone C
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Apache Rotor Systems
Zone F - Wear
– 14% of Pitch Housings failed initial DMWR inspection due to inner diameter wear of bushing exceeding max. limit.
Pitch Housing Analysis
RIMFIRE Reports
DMWR Limit = 2.507 in. maxMean Wear = 0.0014 over limit
This is a repairable location.See Chart 4 for Location
Zone FFr
eque
ncy
0.0030.0020.0010.000-0.001
9
8
7
6
5
4
3
2
1
0
Mean 0.001428StDev 0.001048N 32
Histogram of Zone FNormal
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Apache Rotor Systems
Zone B - Wear
– 37.5% of assemblies failed initial DMWR inspection due to inner diameter wear exceeding max. limit.
RIMFIRE Reports
DMWR Limit = 1.628 in. max
Mean Wear = 0.077 over limit
Lower Shoe Assembly Analysis
Zone B
Zone BFr
eque
ncy
0.270.180.090.00-0.09-0.18
25
20
15
10
5
0
Mean 0.07688StDev 0.1135N 40
Histogram of Zone BNormal
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Apache Rotor Systems
• 48 Lower Shoe Assemblies Inspected in RIMFIRE Project
• 29 Failed Initial DMWR Inspection Criteria
• 60.4% Reject Rate†
Lower Shoe Assembly Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.† Prior to any repairs
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Apache Rotor Systems
Zone C - Wear
– 25% of assemblies failed initial DMWR inspection due to inner diameter wear exceeding max. limit.
RIMFIRE Reports
DMWR Limit = 0.691 in. max
Mean Wear = 0.067 over limit
Lower Shoe Assembly Analysis
Zone C
Zone C
Freq
uenc
y
0.240.160.080.00-0.08-0.16
30
25
20
15
10
5
0
Mean 0.06699StDev 0.1037N 40
Histogram of Zone CNormal
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Apache Rotor Systems
• 106 Hub Subassemblies Inspected in RIMFIRE Project
• 45 Failed Initial DMWR Inspection Criteria
• 42.5% Reject Rate†
Hub Subassembly Analysis
RIMFIRE Reports
* Some parts had more than 1 reason for rejection.† Prior to any repairs
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Apache Rotor Systems
Zone G - Wear
– 15.1% of Hubs failed initial DMWR inspection due to inner diameter wear exceeding max. limit.
Hub Subassembly Analysis
RIMFIRE Reports
DMWR Limit = 9.0475 in. max
Mean Wear = 0.005 over limit
GZone G
Freq
uenc
y
0.0080.0070.0060.0050.0040.0030.002
4
3
2
1
0
Mean 0.005041StDev 0.001388N 15
Histogram of Zone GNormal
Pitting / Corrosion
– 12.3% of Hubs failed initial DMWR inspection due to pitting or corrosion