The Mooney Ovation Ultra, a high-performance single-engine aircraft, is part of Mooney’s long-standing M20 series.1 Throughout its production, the M20 line has utilized different flap actuation systems.2 While earlier Mooney models (pre-1969 M20s) featured hydraulic flaps, the Ovation Ultra and most modern Mooneys, including the M20R Ovation series, employ electrically actuated flaps¹. This distinction is crucial for owners in California, Arizona, and Nevada, as the troubleshooting and repair strategies vary significantly between mechanical/hydraulic systems and electrical ones.
At The Aero Center, our expert technicians are highly proficient in the complex systems of Mooney aircraft, including their flap mechanisms. Our 24/7 service ensures rapid diagnostics and repairs, minimizing your aircraft’s downtime. We operate with the principle of Social Proof, evidenced by the trust Mooney owners place in our specialized knowledge and efficient problem-solving.
UNDERSTANDING FLAP SYSTEMS IN MOONEYS
1. Hydraulic Flaps (Older Mooney Models – Pre-1969 M20):
- Mechanism: These systems used a hand-operated hydraulic pump located in the cockpit, connected to a hydraulic cylinder that extended or retracted the flaps.3 A pressure relief valve allowed for flap retraction.4 The hydraulic fluid reservoir was often shared with the brakes².
- Issues:
- Leaks: Common issues included leaks from the pump, actuator, or hoses. Hydraulic fluid seepage is a visible sign³.
- Loss of Pressure: Flaps might not hold their position or would retract due to aerodynamic forces or spring pressure if the system lost pressure, often due to a leaking check valve or worn internal seals in the pump³.
- Stiff Operation: Accumulation of debris or gelling of old hydraulic fluid could cause stiff pump operation.
- No Longer Available Parts: Overhaul kits for some older hydraulic flap systems are no longer available, leading some owners to consider electric retrofit kits from Mooney¹.
2. Electric Flaps (Mooney Ovation Ultra and Most Later M20 Models):
- Mechanism: The Ovation Ultra uses an electric motor that drives a jackscrew or similar mechanism to extend and retract the flaps. The system typically includes a flap switch in the cockpit (often shaped like a flap for tactile identification), limit switches to control full up and full down travel, and a flap position indicator¹.
- Issues:
- Limit Switch Malfunctions: This is a very common culprit in electric flap systems. If a limit switch becomes faulty, misadjusted, or dirty, the flaps may not extend or retract fully, or they might stop prematurely. For example, flaps might retract only after hitting a bump on the ground, indicating a sticky or intermittent limit switch¹.5
- Electric Motor Failure: The electric motor itself can fail due to wear, internal short circuits, or carbon brush wear. This typically results in no flap movement at all.
- Wiring Issues: Frayed wires, loose connections, or corrosion in the electrical circuit can interrupt power to the motor or limit switches.
- Circuit Breaker Trips: An electrical overload or a binding mechanism can cause the flap circuit breaker to trip. This might happen if the motor is working too hard to overcome friction or a mechanical obstruction.
- Flap Switch Failure: While Mooney’s electric flap switches are generally robust, they can still fail, leading to intermittent or no operation.
- Mechanical Binding: Even with an electric system, mechanical issues in the flap linkages, hinges, or the jackscrew mechanism can cause binding. This puts excessive strain on the electric motor and can lead to circuit breaker trips. Corrosion or debris in the tracks can also cause this.
- Flap Position Indicator Inaccuracy: The indicator might show an incorrect flap setting, even if the flaps themselves are moving correctly. This is usually an issue with the indicator mechanism or its sending unit.
TROUBLESHOOTING AND REPAIR STRATEGIES
General First Steps for Any Flap Issue:
- Pilot’s Operating Handbook (POH): Always refer to the Ovation Ultra’s POH for emergency procedures and flap system limitations.
- Circuit Breaker Check: For electric flaps, check and reset the flap circuit breaker. If it trips immediately again, do not force it.
- Visual Inspection: On the ground, physically inspect the flaps, linkages, and hinges for any obvious obstructions, foreign objects, signs of damage, or binding.
Troubleshooting Electric Flaps (Ovation Ultra Specific):
- Listen for Motor Sound: When activating the flap switch, listen for the sound of the electric motor.
- No sound: Indicates a problem with the switch, wiring, circuit breaker, or the motor itself (no power reaching it, or dead motor).
- Motor sound, but no movement: Points to a mechanical issue (binding, broken jackscrew, disconnected linkage) or a clutch problem within the motor/gearbox.
- Check Limit Switches: This is a common and often tricky area. Mechanics will typically check the continuity and operation of the up and down limit switches. Misadjustment of these switches is a frequent cause of partial flap extension/retraction or “flaps won’t retract” issues after landing¹.
- Inspect Wiring and Connections: Trace the wiring from the flap switch to the motor and to the limit switches, looking for any chafing, corrosion, or loose terminals.
- Inspect Mechanical Linkages: With power disconnected, manually check for free movement of the flap hinges and linkages. Look for any signs of corrosion, wear, or damage that could impede movement. Lubricate as per the maintenance manual.
- Motor/Gearbox Inspection: If all else checks out, the motor or its integrated gearbox may need to be removed for bench testing or overhaul.
Repair Considerations:
- Parts Availability: For the Ovation Ultra, parts for electric flap systems are generally available, either new from Mooney or through authorized parts distributors. Aftermarket PMA parts may also be an option for certain components.
- Specialized Tools and Expertise: Flap system repairs often require specific rigging tools, accurate measurements, and adherence to torque specifications. Improper rigging can lead to uneven flap deployment, control issues, or premature wear.
- Documentation: Any flap system repair that affects its functionality or structural integrity is a major repair and must be documented on an FAA Form 337, signed by an A&P with Inspection Authorization (IA) or by an authorized repair station.
Cost Implications:
- Minor Issues (Adjustment/Lubrication): Can range from a few hundred dollars for diagnosis and minor adjustments/lubrication.
- Component Replacement (Limit Switch, Wiring): Could be in the range of $500 – $2,000, depending on the component and labor.
- Motor/Actuator Replacement/Overhaul: This is a more significant expense, potentially ranging from $2,000 to $5,000+, depending on whether the unit can be overhauled or needs to be replaced with a new or factory-remanufactured unit.
- Extensive Mechanical Linkage Repair: If significant wear or damage to the flap hinges or internal wing structure requires repair, costs can escalate, potentially into the several thousands of dollars due to the labor involved in accessing and repairing these areas.
For Mooney Ovation Ultra owners in California, Arizona, and Nevada, the smooth and reliable operation of your flaps is paramount for safe landings and optimal performance. Regular pre-flight checks and prompt attention to any flap system anomalies by a qualified mechanic are critical.
The Aero Center offers unparalleled expertise in Mooney flap system maintenance and repair. With our 24/7 availability, we minimize your aircraft’s downtime, getting you back in the air with fully functional and safe flaps.
The Aero Center is located at William J. Fox Airfield KWJF | Lancaster, CA. Contact us at 209.885.6950 for questions or appointments.
Footnotes:
- KNR, Inc. “202005 Electric Flap Problems – KNR, Inc.” https://knr-inc.com/shoptalk-articles.html?view=article&id=108:202005-electric-flap-problems&catid=25
- Edwards, W. “Mooney 9351M systems.” https://www.edwilliams.org/m20e/mooneysys.pdf
- Mooneyspace.com. “Hydraulic Flaps Won’t Hold Pressure and Stay Down.” https://mooneyspace.com/topic/42170-hydraulic-flaps-wont-hold-pressure-and-stay-down/