R22 alternator light

[Rick McWilliams]

I made my first night flight in Susies R22. My flying was not very good. The 430 display was too dim and hard to read. The post lights were not aimed quite right. It took more time to scan the new look of the instruments. The night was beautiful. I navigated by roads and GPS. CMA was very quiet. The airport lighting was very beautiful and the runway very long. I decided to approach to the numbers, hover and then depart. As the landing light showed on the runway the alternator light activated. After a short hover I departed for the 7 minute flight to home base. The ammeter showed no discharge with the landing light off. Cycling the alternator switch did not make a change.

 

After landing I found the alternator was very hot. Battery voltage after shut down was 12.7 volts. The next day I did a more complete test run. Battery voltage before start 12.66v. Alternator started at 66 degrees F. With normal instruments on the battery voltage dimished to 12.2 volts, alternator light showed, ammeter showed about -5 A. The clamp on amp prove confirmed -7A at the battery, 0A alternator, 0 A field. Turning on the alternator switch produced 11A alternator and 2A field. The battery voltage rose to 12.9 volts and the alternator light turned off. The alternator proceeded to get hot 210 degrees F. Normal shut down. In the hangar I found that the HID landing lights draw 19A and then dimish to 7A after 30 seconds. The alternator stayed very hot for half an hour. I disconnected the belt and the alternator turned easily indicating no bearing problem. I suspect that there is an internal winding or diode failure. I am having the alternator replaced tomorrow.

 

Do R22 alternators have short lives? This one is clearly a rebuilt unit. What are the other typical mainteneance items for R22?

[ADRidge]

I don't own a helicopter, but I've been around 20 or so different R-22's. I've never heard of an alternator going bad before it was due to be replaced.

[67november]

Alternators in and of themselves are very reliable and a failure of other than a bearing has become extremely rare BUT it's not to say that it cannot happen.

[Mikemv]

Dear Rick, check your maintenance logs to verify replacement and time in service? Also, check with overhaul/rebuilder to see if they will warranty their unit or allow for some credit. Plus, verify that the part is acceptable by part number/serial number. If I remember correctly, you purchased this aircraft from a school. Call the Director of Maintenance at the repair facility to check on history/life of overhauled alternators in use. They are also a source of overhauler/rebuilder. Good luck and keep us posted as to how it turns out. MikeMV

[Goldy]

Rick, I have not seen a lot of alternator issues with Robbies, other than the belt itself. Did the alternator light stay lit once it came on? Or did it come on and then go off a few seconds later?

 

Be sure to check the belt tension as well...

 

Night flying is a blast, but if you havent done a lot of it I would stay away from the coast and some of the dark areas up there.

 

Come down thru Simi or the 101 and check out the SF valley and LA Lights at night. Pretty spectacular.

 

Goldy

[apiaguy]

I've seen lots of alternator failures... diodes, bearings, fans, wobbled out brackets, misalignment, brushes, brush blocks.. etc.. all occured before engine tbo.

 

I took my airplane checkride in a 172 that had 2 diodes out... if you turned on the rotating beacon with the radios on the low voltage light would flash in unison with the beacon.. I inconspiciously turned it off for our flight and he never noticed... it would also come on if rpm was below about 1200rpm..

Edited March 3, 2010 by apiaguy

[ironranger]

Rick did you consider just landing at the airport you were at and catching a ride home. I would have been concerned especially flying at night that the battery could drain down causing a loss of electrical, which would affect lighting, communications, and tach/govenor control.

 

IR

[Rick McWilliams]

I could have landed at CMA. That would have been more correct. It would have been a 5 minute trip around the pattern. I choose the 7 minute trip for probably the wrong reasons.

 

The new alternator was installed today. It works much better,comes right up to 14.4 volts with a field current of 0.5A to get 20A alternator output. Case temperature is now cooler than the starter. The Robinson rebuilt alternator has painted laminations and looks new.

 

I suspect that the sick alternator was struggling to keep battery voltages up to 13V. The governor is more accurate and clutch is faster.

[kodoz]

That would have been more correct. It would have been a 5 minute trip around the pattern. I choose the 7 minute trip for probably the wrong reasons.

 

At least you recognize that. My instructor and I used to go through this routine whenever a flight (or continuation of a flight) was in question..."yeah, we could do that, but how exactly would the NTSB report read? Cause of the accident was the pilot's decision to continue despite..."

[r22butters]

The R22's alternator looks exactly like the one in my old Mustang, and I've had to replace it many times.

 

I had the light come on once, we called the mechanic after landing 20min. later. He said just to clean up the connections and it should be ok. We did, and the light went out, however, after another day of flying it needed replaced. These things happen.

 

You should keep an eye on the landing lights (nav also), they tend to burn out easily, especially with prolonged hovering. I've had to cancel quite a number of night flights due to those damn lights.

[Goldy]

You should keep an eye on the landing lights (nav also), they tend to burn out easily, especially with prolonged hovering. I've had to cancel quite a number of night flights due to those damn lights.

 

Thats what's great about the new HID landing lights, no filament to break!

[Mikemv]

To All, if possible, always install the landing lights with the filament in a vertical position rather than a horizontal position. Less lateral vibration compared to vertical vibrations saves the bulbs. As Goldy said, HID are the best as are LED nav/pos & anti collision lts!

[Goldy]

To All, if possible, always install the landing lights with the filament in a vertical position rather than a horizontal position. Less lateral vibration compared to vertical vibrations saves the bulbs. As Goldy said, HID are the best as are LED nav/pos & anti collision lts!

 

 

Mike, wow, that makes a ton of sense, yet I have never heard of anyone doing it! I'm gonna check the 44 next week just to see what the orientation is! And yes, I have seen ships in the air at night with the newer style LED's...visible from twice the distance of a standard strobe!

 

Rick- you could always park at CMA if you want, just steal the ground wheels (over next to 8SS) and park it right next to the 44!

 

Goldy