What does it mean when a engine generator fails on an aircraft (Dornier DO-228)?
I was reading an article about the air plane crash in Nepal where the pilots reported that the engine generator had failed on their Dornier DO 228. What does that mean and what does that entail (as far as measure a pilot can take to fly the plane). I thought you can play a twin engined plane even if one of them fail….anyone has any insight. (we know there was bad weather but still…)
A CSD generator is only found on jets engines. There are usually 3 on a jet aircraft, one for each engine and another in the APU.
This supplies a constant frequency output which allows a steady AC current regardless of engine performance. The Engine driven generator isn’t directly connected to the engine shaft, but through a drive unit that can disconnect itself completely from the engine in the event of engine malfunction.
Which is why if a generator fail was to occur in flight, the crew can diconnect the effected generator (which cannot be reconnected in flight), the crew can/could transfer the AC power to the APU or leave the effected Bus off without it having an effect on the engine.
Each aircraft system powers off a particular AC system , and DC transformer rectifier systems are there to power AC systems and for redundancies for limited standby power in the event of AC power loss.
(DC battery can power AC standby bus via a static invertor if AC fail). If the left engine gen fails, then that particlar AC is effected and can be transfered to the APU bus etc.
The dornier DO-228 doesn’t have a CSD but a starter/generator like most turbo props. It has the ability to use DC power from it’s battery source to power the starter generator and start the engine (for engine combustion) to produce mechanical torque. The torque from the engines produce an alternating current from the generator. Unlike the CSD the starter/generator is connected to the mechanical shaft of the engine.
The reason why the Dornier 228 crew notified ATC regarding generator trouble is probably due to RPM/engine fluctuations on each engine which eventually led to a failure on both engines
One of the 1st indications of engine problems is generator/electrical problems, if the engine is unable to provide a high enough RPM the engine driven generator is unable to produce enough AC power for the effected systems.
It would seem unlikely that the generators are a lkely cause of a dual engine failure, but merely just an early indication of engine problems.
From the news, the crew lost both engines in IMC (and with all AC power off, no instruments etc) the crew consequently crashed.
Too early to tell the direct cause however…
4 Comments »
Wade H said :
August 24, 2010 at 6:51 am
While I don’t know about that particular plane, in some designs even when there are two engines there is only one generator. Obviously, if power completely fails after the bats go flat there can be complications to various systems requiring power. Some instrument packages require power. Some Landing Gear systems require power. Some airplanes even fly by wire these days, making control impossible.
If instruments are electronic and the power fails in cloud, much less storm, instrument flying can turn into vertical descent in as little as a few seconds and one doesn’t even have a radio tower to tell one ones going down.
There is nothing quite like coming out of cloud and finding ones self staring at a cliff face wider than the window.
References :
Caretaker said :
August 24, 2010 at 6:54 am
Giving credit to your question as a general question. In the days of Recips with CSD, Constant Speed Drive Generators. If the Generator failed the engine would continue to make it turn and you would have a catastrophic heat issue in the engine nacelle. Not a good event. Probably not the answer you need cuz flight has changed
References :
sodiq lawal said :
August 24, 2010 at 6:54 am
in planes electricity for the plane is generated by a generator attatched to the engine. when it fails the aircrafrt no longer recieves electricity
References :
gisburnuk said :
August 24, 2010 at 8:05 am
A CSD generator is only found on jets engines. There are usually 3 on a jet aircraft, one for each engine and another in the APU.
This supplies a constant frequency output which allows a steady AC current regardless of engine performance. The Engine driven generator isn’t directly connected to the engine shaft, but through a drive unit that can disconnect itself completely from the engine in the event of engine malfunction.
Which is why if a generator fail was to occur in flight, the crew can diconnect the effected generator (which cannot be reconnected in flight), the crew can/could transfer the AC power to the APU or leave the effected Bus off without it having an effect on the engine.
Each aircraft system powers off a particular AC system , and DC transformer rectifier systems are there to power AC systems and for redundancies for limited standby power in the event of AC power loss.
(DC battery can power AC standby bus via a static invertor if AC fail). If the left engine gen fails, then that particlar AC is effected and can be transfered to the APU bus etc.
The dornier DO-228 doesn’t have a CSD but a starter/generator like most turbo props. It has the ability to use DC power from it’s battery source to power the starter generator and start the engine (for engine combustion) to produce mechanical torque. The torque from the engines produce an alternating current from the generator. Unlike the CSD the starter/generator is connected to the mechanical shaft of the engine.
The reason why the Dornier 228 crew notified ATC regarding generator trouble is probably due to RPM/engine fluctuations on each engine which eventually led to a failure on both engines
One of the 1st indications of engine problems is generator/electrical problems, if the engine is unable to provide a high enough RPM the engine driven generator is unable to produce enough AC power for the effected systems.
It would seem unlikely that the generators are a lkely cause of a dual engine failure, but merely just an early indication of engine problems.
From the news, the crew lost both engines in IMC (and with all AC power off, no instruments etc) the crew consequently crashed.
Too early to tell the direct cause however…
References :
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