In 2021 I assisted a UK builder get approval of the SDS system on an RV10 project. Below is the reliability data (updated to 2023), received from SDS, that was used in support of the approval process. The stats have been compiled from the past 29 years speak for themselves.
Overall Statistics
- 950,000 + flight hours on over 2,450 systems
- High time ECU- 145,000 hours (bench test unit)
- High time fliers of our systems
- 1,500 hours (Rover V8)
- 2,500 hours (Lycoming O-360 and Subaru)
- 2 at 2,300+ hours (Rotax 912 and Jabiru used for flight training)
- High time Lyc./ Subaru (same airframe) 2,800 hours
- Jabiru 2300+ hours
- High time Rotax 3,000 hours
Component Failures
The statistics below are based on reported failures only.
Critical Components
- ECU failures on aircraft 1 (continued flight was possible due to dual ECU installation)
- Crank sensor failures 0
- Injector failures 2 (reported but unconfirmed)
- TPS failures 3 (only 1 failure in past 15 years after sealed unit design)
2 injector failures were reported but not confirmed as parts were not returned for inspection. We have sold over 10,000 aviation and automotive systems incorporating 40,000+ injectors. Over 27 years these are the only reported failures.
Non-Critical Components (continued flight possible despite failure)
- 4 cylinder coil pack failures 3 (dual coil packs provide redundancy similar to magnetos)
- 6 cylinder coil pack failures 4 (dual coil packs provide redundancy similar to magnetos)
- Fuel pump failures 5 (dual electric fuel pumps provide redundancy)
- Temp sensor failures 2 (No failures in past 9 years since sensor design change)
- MAP sensor failures 6 (4 due to water contamination from improper installation)
- Wiring harness failures 0
Incidents / Accidents involving failure of SDS equipment
Note: Below details instances where SDS equipment failed and the reason for the failure.
- A forced landing was reported with the cause determined to be incorrect wiring. An injector wire was โpinchedโ to ground causing failure of the injector. The same installation reported intermittent engine running which was traced to an improper injector wiring.
- A V6 Titan T51 experienced an engine failure and forced landing when a user installed aluminum exhaust system collapsed under the heat load and melted through the Hall sensor cable. Subsequent to this incident SDS upgraded Hall sensor cables to fire sleeved Tezfel wires.
- A plane limped around the pattern after takeoff on 3 of 4 cylinders with an apparently dead injector (low EGT and CHT indication). Landed safely. Injector was checked extensively โ no fault found. ECU was changed out and old one sent to SDS for examination. No fault found – ECU has been running perfectly in shop car for over 4 years now. An unidentified wiring issue is the likely cause as no fault was found with the ECU or other SDS supplied components. The aircraft ignition was another brand, not SDS.
- A stall / spin fatality resulted from an engine failure at 300 feet after take-off. The root cause of the engine failure was found to be incorrect wiring of the SDS system by a licensed aircraft mechanic. The ECU and coil pack circuits were wired to the wrong breaker values causing the breakers to trip when under load.
- Chip failure from unknown causes resulted in ECU shutdown. Aircraft returned to base on backup ECU.
- There have been 3 reports of 3rd party ignition drivers (non-SDS) attached to SDS systems which failed from poor/cold solder joints, fortunately all on the ground. These modifications were not approved by SDS.
- 15+ reports of rough running/engine shutdowns in flight. Causes determined to be:
- Use of incorrect spark plug wires
- Routing of sensor wires alongside spark plug wires
- Use of non-resistor plugs contrary to SDS requirements
- Bad grounding
- Water damage to ECUs arising from incorrect ECU installation (ECUs are not exposure proof).
- Unapproved, 3rd party parts added to SDS electronics
- Impropercrimping of connector pins
- Inadequate chaff protection
- Insufficient strain relief of wiring.
In most cases aircraft landed safely either on the single ECU or by switching to the backup ECU.
Typically, when customers report system problems with SDS supplied equipment, the problems are traced to a failure to install, wire and configure hardware in accordance with SDS instructions.