Greg_Toman
Member
I recently was flying my RV-6A on a low visability day, and stumbled into some very heavy mist, clouds and light rain. I had flown about 10 minutes into these conditions when I deemed it prudent to land at a nearby airport.
The OAT was about 40 deg F aloft, and I had no reason to suspect icing conditions were present, however, when I made my approach to land, I had a sense that something was not right with the airspeed, as it was indicating 100 mph on what seemed like a normal approach (75-80 mph). Luckily I ignored the airspeed, and landed without using it. (Looking back on it, I was amazed how easy this was...this was partly due to the long runway I was landing on.)
My EFIS, my mechanical backup ASI, and my EIS, which all use the same pitot/static port, showed the same indications.
In an event, as I touched down, in my normal landing attitude, and what seemed like my normal touchdown speed (about 60 mph), I glaced down and saw the airspeed indicator reading over 90 mph...clearly wrong. As I taxied off the runway (10 mph), the airspeed was slowly decaying down through 50 mph, and by the time I parked, it was down to zero.
I checked the pitot and static system for water by blowing it out. Only a fraction of a drop of water came out of the pitot tube...nothing from the static ports as near as we could tell.
No problems have occurred since then.
Has anyone had any experience like this?
I am going to test a second pitot/static port system that one of our customers suggested. This is to use the air pressure on top of the engine (before it has gone through the baffling) as the pitot source, and the cabin air as the static source. Our customer said it worked good for him as a backup, and it probably offers some icing protection.
Still, I would like to know why happend that day. In 300 hours, including flying in snow, rain, freezing and hot conditions, it only occurred that one time. Has anyone else had such an experience?
Thanks
Greg Toman
RV-6A 269DB
Building RV-10
The OAT was about 40 deg F aloft, and I had no reason to suspect icing conditions were present, however, when I made my approach to land, I had a sense that something was not right with the airspeed, as it was indicating 100 mph on what seemed like a normal approach (75-80 mph). Luckily I ignored the airspeed, and landed without using it. (Looking back on it, I was amazed how easy this was...this was partly due to the long runway I was landing on.)
My EFIS, my mechanical backup ASI, and my EIS, which all use the same pitot/static port, showed the same indications.
In an event, as I touched down, in my normal landing attitude, and what seemed like my normal touchdown speed (about 60 mph), I glaced down and saw the airspeed indicator reading over 90 mph...clearly wrong. As I taxied off the runway (10 mph), the airspeed was slowly decaying down through 50 mph, and by the time I parked, it was down to zero.
I checked the pitot and static system for water by blowing it out. Only a fraction of a drop of water came out of the pitot tube...nothing from the static ports as near as we could tell.
No problems have occurred since then.
Has anyone had any experience like this?
I am going to test a second pitot/static port system that one of our customers suggested. This is to use the air pressure on top of the engine (before it has gone through the baffling) as the pitot source, and the cabin air as the static source. Our customer said it worked good for him as a backup, and it probably offers some icing protection.
Still, I would like to know why happend that day. In 300 hours, including flying in snow, rain, freezing and hot conditions, it only occurred that one time. Has anyone else had such an experience?
Thanks
Greg Toman
RV-6A 269DB
Building RV-10