The pilot was conducting a local personal flight in the experimental, amateur-built Zenith CH-601. During cruise flight, the voltmeter’s indications became erratic and shortly after the airplane experienced a total loss of electrical power.
The engine subsequently lost power, and the pilot conducted an emergency landing near Ocean Shores, Washington, during which the bottom of the fuselage contacted surrounding vegetation.
The right wing then dipped, and the airplane hit terrain.
The pilot reported that, following the accident, he checked the battery’s charge, and it was 11 volts. The electrical system on the airplane required 12 to 13 volts for operation.
The pilot partially disassembled the airplane following the accident, and the engine, most of the flight instruments, the tachometer, and the interior components were not available for examination. Therefore, a thorough evaluation of the airplane’s electrical system was not possible.
However, the battery examination revealed that it had a 10-volt charge, indicating that either a battery or charging system failure occurred.
The fuel delivery system included two electronic fuel pumps connected in series with no mechanical or auxiliary pumps installed. Therefore, the loss of electrical power would have disabled both fuel pumps and resulted in fuel starvation and a loss of engine power. There was no other method to deliver fuel to the engine if the battery power was insufficient to power the fuel pumps.
Probable cause: A reduction in electrical power, which disabled both fuel pumps and resulted in fuel starvation and a loss of engine power.
NTSB Identification: WPR16LA164
This August 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
I have an electrically dependent engine, it will require both, failure of the alternator and low battery voltage to make the engine quit. If the alternator fails, the engine will run on battery alone for about 2 hours. Risk management dictate taking off having a good, fully charged battery (at least 13 volts) and flight plans with airports reach within 1 1/2 hours. If the battery is low it will run as long as the alternator is working.
If the alternator fails and the pilot continues to fly until the battery is drained bellow minimum voltage, engine will quit. It can also quit if an electrical component is drawing to much current above the charging capacity of the alternator.
The FAA Registry http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=619LD
shows this CH-601 used a Continental engine, probably an O-200. The registry had no detail.
The O-200/ O-300 has no mechanical fuel pump, since the certified aircraft it is used in are high wing, so use gravity to flow fuel.
The CH-601 is a low wing, so the fuel must be pumped to the carburetor. I’m not aware of any way to add a mechanical fuel pump to this engine.
I better fuel system design would use a backup battery to run the fuel pumps, and a warning light when the alternator fails and the battery voltage drops below 12.5 volts.
There was no info on the battery used in the NTSB docket. I would recommend always using a certified aircraft battery; Concorde or Gill.
A correction ; the Cont. O-200 has 2 mounting pads for a mechanical fuel pump, but both are optional parts, and are not part of the base engine.
So, this aircraft could have had an engine driven fuel pump, but the builder chose not to install one.
I have been using an Odyssey PC680, which is the recommended battery for RV’s for the past 10 or 12 years. They are extremely reliable and much lighter than a Concord or Gill battery.
While they can fail, my experience indicates they are much more reliable than traditional aviation batteries.
Note, these are not lithium batteries.
Experimental aircraft can use any battery that the owner/pilot chooses.
If you get good service from a 14 amp-hour battery, good.
My experience troubleshooting aircraft that have been using a low AH battery to crank a high compression engine using an aftermarket ‘lighweight’ starter is that the small battery cannot reliably provide the 400-600 amps required to crank the engine..
My Cessna requires a certified battery, and I like having 24 AH and 800 amp cranking current. The 23 lb weight is 9 lb more than the light weight batteries…I’ll gladly trade 1.5 gallons of fuel for a larger battery.
My Concorde RG battery has been very reliable and holds a full charge for weeks.
Depends on the aircraft. Some are gravity feed to a carburetor, some are mechanical pump with an electric pump backup for fuel injection or a carburetor. Homebuilt/experimental is a different animal. Having a single point failure depending solely on electric power for fuel flow is not wise.
Maybe someone more familiar with that particular homebuilt type will discuss the system and common options.
Well, that’s a refreshing change. At least he didn’t run out of gas.
Let me show my ignorance for just a second. This was a home built which means he could have pretty much done what he wanted to do with the fuel system. Two pumps in series were the only way that fuel could be gotten to the engine. Is it not a good idea to have a back up system independent of the first system that will get fuel to the engine? Is that how it’s done and most GA aircraft?
Yes – every production model I can think of that is not gravity fed has first, an engine driven fuel pump, then second, an electrically powered back-up or boost fuel pump. You could have an engine driven fuel pump malfunction, and a total electrical system failure leaving you in the same dilemma, but two sounds a lot better than one.