# Presentation: 483909

## Powerplants and Maintenance Issues

- Dave Keenan
- Powerplants Group Chairman

## Powerplants and Maintenance Issues

- Right Propeller
- • 	Right Engine
- • 	Time Between Overhauls
- • 	Approved Airworthiness Inspection Program
- • 	Engine Maintenance Issues
- • 	Conclusions

## Right Propeller

**Manufacturer** – McCauley Propeller Systems
- 			        Piqua, Ohio
**Model** – 3AF32C505-C
**Characteristics:**
- Three Bladed
- Dual Acting
- Constant Speed
- Full Feathering

## Right Propeller Findings

- External
- All propeller blades and counterweights were in place and intact.
- Blade angles measured 82.2°, 82.4°, and 82.3°.
- Feather angle is 82.2° (± 0.3°).
- Internal
- All internal components were intact and undamaged.

## Right Propeller Conclusions

- The propeller was fully feathered when the airplane contacted the water.
- 		•  Measured blade angles
- 		•  Lack of damage to blades and 		    		   internal operating mechanisms

## Right Engine

**Manufacturer** – Teledyne Continental Motors 			        Mobile, Alabama
**Model** – TSIO-520-VB
**Characteristics**
- 	        • Turbocharged, fuel-injected, air-cooled,  	   reciprocating engines
- 		•  Rated for 325 horsepower, at a power 	   setting of 2,700 RPM with 39 inches of 	   mercury manifold  pressure up to an altitude 	   of 12,000 feet.

## Right Engine Findings

- The No. 2 cylinder was separated from the engine, and its piston was fragmented.
- The No. 2 cylinder was generally intact.
- Cylinder hold-down studs (10)
- Three studs were intact with their threads undamaged.
- Six studs were fractured in high stress fatigue.
- Two loose hold-down nuts were recovered from the engine compartment.

## Engine Maintenance Issues

- The right engine had accumulated 2,270.6 hours time since overhaul (TSO) at the time of the accident.
- TCM Service Information Letter SIL 98-9A recommends a 1,600 hour TBO interval.
- Air Sunshine was operating to a TBO of 2,400 hours in accordance with FAA Aviation Safety Inspector Handbook 8300.10.
- A requirement for Air Sunshine to obtain these TBO increases was that they develop their own Approved Aircraft Inspection Program (AAIP).

## Engine Maintenance Issues

- Differential compression tests
- Theory
- The last differential compression test of the No. 2 engine was performed during a Phase 1 inspection on June 12-14, 2003.
- The results indicated that there were two cylinders with abnormally low readings and a third, the No. 2 cylinder, that held no pressure at all.

## Engine  Maintenance Issues

- Engines last overhauled in December 1999.
- No logbook entries for any cylinder changes since the time of the last overhaul.
- The No. 6 cylinder had been removed and replaced between the last engine overhaul and the accident flight.
- The results of the last differential compression test (6/03) would have been enough justification to have removed, inspected, and replaced the No. 2 cylinder while troubleshooting the low reading.

## Right Engine Conclusion	

-  The simultaneous loosening of two or more of the right engine No. 2 cylinder hold-down nuts resulted from the application of insufficient torque, which was most likely applied by Air Sunshine maintenance personnel during undocumented maintenance.