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MMOPA 2013 Piston Engine SeminarBy Chad Menne / Malibu Aerospace

Teledyne Continental Motors “Gold Motor”

Textron Lycoming “Grey Motor”

• Chad Menne • Owner - Malibu Aerospace • Maintain over 100 PA46s/year • Over 9,000 hours of PA46 time • Corporate flight experience • Aircraft management • Flight test experience

• Engineering – Research & Development • FAA Certification Tests • Maintenance / Production Flight Tests

Who am I and why are we here?

• Both Lycoming & Continental Engines • How do we operate these engines? • Why do we operate them that way? • What are we missing? • What is my mechanic missing? • What are common problems?

Today’s Topics

• 98 out of 1385 total accidents were due to powerplant failures (7%),

representing 21.4Million flight hours (Nall report 2007).

• That is one ACCIDENT every 218,367 flight hours caused by engine failures,(turbine & piston), vs one accident every 15,451 hours for ALL causes.

• You're 14 times more likely to have an accident caused by something other than an engine failure.

• 11 of them resulted in FATALITIES (0.8%), which equals ONE fatal accident every 1,950,000 flight hours due to engine failure.

• The TOTAL FATAL accident rate is 1 per 84,920 flight hours for ALL types of accidents in ALL types of planes.

• You're 23 times more likely to have a FATAL accident caused by something other than an engine failure.

Engine Reliability

0

350

700

1050

1400

Total Accidents Engine Accidents Total Fatal Engine Fatal11252981,385

Accidents (21,400,000 Hrs)

• The piston PA46 fleet averages about 150,000 hours/year

• That means we should see one accident every 1.5 years and one fatal accident every 13 years due to engine failure (piston & turbine)

• Some sources claim a piston engine fails every 3,200 flight hours. Pratt & Whitney claims a PT6 failure every 333,000 flight hours by comparison.

• If the data is correct,(it's difficult to find concrete data), the we should see approximately 47 piston engine failures per year in the PA46 fleet. Either we are maintaining these engines much better than normal, we aren't hearing about the failures, or it may be that a precautionary landing due to an engine problem,(such as rough running), may be counted as an engine failure.

Engine Reliability

• Both Malibu & Mirage ◦ Exhaust!

• Turbo transitions, slip joints, gaskets, clamps ◦ Magnetos

• Cam wear, moisture/corrosion, points, dist. block ◦ Turbochargers

• Don’t expect them to go to TBO ◦ Cam & lifter corrosion and wear

• Excess moisture, fuel dilution, shearing & thermal breakdown of the oil

◦ Spark plug resistor failures • Measure resistance, it must be under 5,000 Ohms

Common Problems

Magneto Pressure Leak

Spark Plugs

Massive Plug Fine Wire Plug (broken)

Spark Plugs

Broken Insulator Rusty Plug Core

• Exhaust valves ◦Most common cause from high power & high CHT & exhaust temps

• Starter drive adapters ◦Lightweight Iskra starters can cause premature wear ◦Air conditioner driveshaft seals can leak

• Cylinder & ring wear ◦First to be blamed & rarely the cause

• Bearing end play ◦Check for proper end play during pre-flight and DO NOT fly without

end play! • Borescope for detailed inspection before condemning a

cylinder • Be sure to use TCM master orifice tool for daily calibration

during a compression check

Malibu specific problems

• Exhaust valve guide wear (high oil consumption and rough running)

• Broken oil control or compression rings • Poor break-in results (high oil consumption) ◦Lycoming does not allow mineral oil

• Cracked oil sump at turbo support studs • Cracked internal oil baffle ◦Be sure to check suction screen for rivets

• Fuel servo problems ◦Unable to get proper ground mixture or full power fuel flow ◦Can cause surging in cruise

• Fuel line AD 2011-06-04 every 100 hours (cracking due to improper securing of lines)

Mirage specific problems

Ring Problems

Broken Piston Rings Broken Oil Control Rings

Ring Problems

Overheated Piston Ring Low Tension Blow-by

Heat Problems

Burned Oil On Pistons Signs of Heat

Valve Problems

Worn Exhaust Valve Worn Valve & Guide

TCMLycoming

Valve Problems

Burned Exhaust Valve Burned Valve Seat

Believe it, or not!

Lifter Main bearing

Crankcase bearing journal

Crankshaft Bearing Wear

Oil Sample - Good

Oil Sample - Bad

• Iron • Cylinders, rotating shafts, valve train and any steel part sharing the oil. • Copper • Brass or bronze parts, bushings, bearings, oil coolers, sacrificial coatings. • Nickel • Valve guides, trace element in steel, some cylinder types. • Chromium • Rings, cylinders, a trace element in steel. • Silver • Sacrificial coatings, a trace element in some types of bearings, bearing cage plating • Magnesium • Engine casings, additives • Aluminum • Pistons, piston pin plugs, bearing overlay, casings. • Lead • Primarily leaded gas blow-by, traces from bearings • Silicon • Abrasive dirt from intake air, silicone sealers and gaskets, sample contamination. • Tin • Bearings, bronze parts (with copper), anti-wear coatings. • Molybdenum • Traces of anti-wear coatings, some cylinder types, and bearings.

Most Common Sources of Wear Metal Elements in Oil

Exhaust Woes

Leaky Gasket Exhaust Gasket

Mirage Turbo Transition

Heavy, Cast Inconel Erosion & Blistering

Malibu Turbo Transition

.065” Stainless Steel Check at EVERY Oil Change!

Tailpipe Trouble

Corrosion has its way Heat Muff - Uncovered

V-Band Clamps

Exhaust Clamps

Malibu & Old-Style Mirage Clamps Crack from over-tightening

Exhaust Clamp Engagement

The right way The WRONG way

Sump Cracks (Turbo Mounts)

Sump Repair

Oil Sump Baffle

Oil Sump Baffle

Cracked Oil Baffle Crack at screw attachment hole

Turbochargers

• Compressor damage • Bearing failure • Seal failure • Scavenge pump failure • Scavenge hose failure • Wastegate failure or sticking • Broken or missing mount hardware

Common Turbo Problems

Turbochargers

Bearings Compressor Damage

Turbo Trouble

Carbon Buildup Flange & Clamp Leakage

Engine Cooling

Alternate Air Box Linkage

Wastegate Actuator

Check for oil in drain

Check linkage for wear

Check spring for wear against tab

Broken Rings

Check suction screen for parts during oil changes

Missing Baffle Hardware

Watch for missing bolt in RH Fwd baffle

Common Baffle Cracks

Intercooler "tool shelves"

This is what happens when a tool or part is left on top of

the intercooler in flight

Broken Filter Drain Tube

• Vent oil cap after shutdown (minimize corrosion) • Watch EGTs and trend data (ignition and fuel

injection anomalies) • In-flight mag checks (look for hot or cold EGTs) • Oil samples (watch for iron, nickel, almuminum) • Watch for peak TIT drift (up or down) ◦Drift up is usually ignition or low compression ◦Drift down is usually a probe going bad

Things that you can do for your engine

• The best way to prolong your engine’s life and improve safety is to know how to balance parameters ◦Trade one temp for another ◦Engine limits are not intended to provide longest life, but

are instead proven to be acceptable for short durations ◦Add fuel only as necessary to achieve a good balance

during climb • Less fuel means more power! (power means heat)

The best pilots can juggle

A. 360° CHT – 1650° TIT B. 400° CHT – 1580°TIT

Which is worse???

A. 360° CHT – 1650° TIT ◦ The TIT is an exhaust gas temp, the CHT

affects the engine’s ability to dissipate heat ◦ A cooler CHT can transfer more heat away

from a valve B. 400° CHT – 1580°TIT ◦ Less differential from valve to seat and guides

removes less heat from valve ◦ Localized oil temps will be hotter at valve

guides & pistons

Which is worse???

Settings to think about

1kt loss from 50 RPM less and leaned .6 GPH less for same CHT

2kt loss from 140 RPM less and leaned 1.9 GPH less with 10 degree cooler CHT

1kt loss from 110 RPM less and leaned 1.6 GPH less with 8 degree cooler CHT

1kt loss from 90 RPM less and leaned 1.2 GPH less with 2 degree cooler CHT

2kt loss from .8" Hg less and leaned 1 GPH less with 4 degree cooler CHT

6% speed loss for 21% fuel savings LOP vs ECON cruise _________________ 11% speed loss for 35% fuel savings LOP vs NORM cruise

Mirage with fresh TOH, ISA+10 conditions

• How hot is too hot??? ◦CHT or EGT/TIT, not both (valve wear) ◦High TIT means more exhaust wear

• Lean of Peak, no free lunch ◦Lose speed (less power at same power setting) ◦Wear exhaust (higher EGTs, more oxidation) ◦Not as smooth (slight roughness or surging) ◦Cooler CHTs (helps offset the higher EGTs and cool

valves)

Operations

• Continental ◦20% fuel savings ($28,000 over 2000 hours)

• 1500 hrs x 21GPH x $4.50/gal - 20% ◦ 2% speed loss ($9,000 additional aircraft cost over 2000 hours)

• 1500 hrs x 200kts - 2% / 196kts x $300/hr ◦ Increased exhaust wear costs ($3000 over 2000 hours)

• Lycoming ◦ 25% fuel savings ($35,000 over 2000 hours)

• 1500 hrs x 21GPH x $4.50/gal -25% ◦ 10% speed loss ($50,000 additional cost over 2000 hours)

• 1500 hrs x 200kts - 10% / 180kts x $300/hr ◦ Increased exhaust wear costs ($10,000 over 2000 hours)

LOP Cost Comparison

• How to change your ignition timing??? ◦Engine speed

• Higher RPM = less advance (less time to burn) • 2500 RPM = 1 Revolution every .024 seconds

• Lower RPM = more advance (more time to burn) • 2300 RPM = 1 Revolution every .026 seconds or 9% more time

◦ Mixture ratio ROP • Leaner mixture = more advance (burns faster – sharper power pulse) • Richer mixture = less advance (burns slower – softer power pulse) ◦ Mixture ratio LOP

• Richer mixture = more advance (burns faster – sharper power pulse) • Leaner mixture = less advance (burns slower – softer power pulse)

Ignition timing and combustion speed

• Lower RPM

• Higher RPM

Affects of RPM on “Combustion timing”

Earlier Peak Pressure, More Time to Burn, More Cooling Time per Cycle, Less HP, Cooler EGT, Cooler CHT, Higher Turbo Speeds

Later Peak Pressure, Less Time to Burn, Less Cooling Time per Cycle, More HP, Hotter EGT, Hotter CHT, Lower Turbo Speeds

Intake Compression Exhaust

Intake Compression Combustion Exhaust

Combustion

TDCPeak Pressure

TDCPeak Pressure

(Approx. 4% more time per 100 RPM)

• ROP Combustion

• LOP Combustion

Affects of mixture on “combustion timing”

Faster Combustion, Sharper Pulse, Cooler EGT, Hotter CHT

Slower Combustion, Lower Pressure, Hotter EGT, Cooler CHT

Intake Compression Combustion Exhaust

Intake Compression Combustion Exhaust

TDCPeak Pressure

TDC Peak Pressure

• Rich of peak, lean to peak, lean of peak • TIT peak method, a.k.a.“the factory method” • Fuel flow method • JPI lean find “Lean L” method • JPI lean find “Lean R” method • “The big pull”

Leaning TechniquesNo wonder you’re confused!

• Continental ◦LOP, FF x 15 = HP ◦ROP, FF x 13.25 = HP (Can vary a lot)

• Lycoming ◦LOP, FF x 14 = HP ◦ROP, FF x 12 = HP (Can vary a lot)

What’s My Horsepower???

Thank you!

• Questions • Comments • E-mail me, cwmenne@malibuaerospace.com • Fly Safe!