KPDX From United States of America, joined Dec 2005, 2526 posts, RR: 3 Posted (2 years 9 months 1 week 1 hour ago) and read 11353 times:
Hi all.
I was at the Oregon International Airshow today (Saturday) in Hillsboro, Oregon. About 4 PM I looked up and saw a plane at high altitude with a fairly good sized contrail flying West-bound towards the Oregon Coast and Pacific Ocean. The plane looked "odd" to me so I got out my video camera and zoomed in.... It was a all-white Dash 8 Q400! How weird is that?
Why would it be at such high altitude heading towards the ocean around Portland? I got a little of it on video, but stupidly enough I didn't get the contrail in it.
Also I should add, I am assuming it was a Horizon Q400.
Thanks
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Not weird at all.... Contrails depend on several factors. The temp aloft, the relative humidity aloft, the temp of the exhaust and the humidity of the exhaust. Jets are not the only ones that will leave them. Just look at pictures of the B-17's during WWII
"It's not the size of the dog in the fight, but the size of the fight in the dog"
The contrails were cool but I was mainly talking about the fact that it was at such a high altitude (it was really high up) and heading westward over Portland, OR.
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CBPhoto From United States of America, joined Dec 2003, 1508 posts, RR: 6 Reply 4, posted (2 years 9 months 1 week ago) and read 11164 times:
Quoting KPDX (Reply 2): The contrails were cool but I was mainly talking about the fact that it was at such a high altitude (it was really high up) and heading westward over Portland, OR.
Agreed, slightly mis-leading. However, I can assure you, the Q400 was not any higher then 25,000 ft, as that is the service altitude of that aircraft! So in all reality, it really was not "that" high!!
KPDX From United States of America, joined Dec 2005, 2526 posts, RR: 3 Reply 5, posted (2 years 9 months 1 week ago) and read 11145 times:
Argh... cmon guys, be easy on me. I got excited.
Anywho, for normally seeing Q400's at 15,000 or so... yeah it seemed a bit high. I am not saying it was at 30,000 feet or anything... Just higher than I personally have ever seen a Q400.
*Puts mental notes to not get so excited while typing out a post.
[Edited 2010-08-21 23:49:57]
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DocLightning From United States of America, joined Nov 2005, 16831 posts, RR: 57 Reply 6, posted (2 years 9 months 6 days 23 hours ago) and read 11041 times:
Quoting EMBQA (Reply 1):
Not weird at all.... Contrails depend on several factors. The temp aloft, the relative humidity aloft, the temp of the exhaust and the humidity of the exhaust. Jets are not the only ones that will leave them. Just look at pictures of the B-17's during WWII
Water vapor is one of the two major products of a hydrocarbon combustion reaction. CO2 is the other. Given the right altitude, temperature, and ambient humidity, any such reaction will produce visible condensation, whether it is a piston engine, a turbine, or a bunch of angels using lighter fluid to start their backyard (backcloud?) grill.
KPDX From United States of America, joined Dec 2005, 2526 posts, RR: 3 Reply 8, posted (2 years 9 months 6 days 22 hours ago) and read 10864 times:
Thanks for the information about the contrails guys. Now does anyone have an idea why a Q400 was flying that high over Portland heading towards the Pacific Ocean?
Thanks
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FlyASAGuy2005 From United States of America, joined Sep 2007, 6520 posts, RR: 11 Reply 10, posted (2 years 9 months 6 days 16 hours ago) and read 10386 times:
Quoting KPDX (Reply 8): Thanks for the information about the contrails guys. Now does anyone have an idea why a Q400 was flying that high over Portland heading towards the Pacific Ocean?
You said it was all white? Is it possible it was a ferry fight up to Alaska for a Horizon repositioning? (stops on the way of course).
CAM2:"Lightning coming out of that one." CAM1: "What?"
KPDX From United States of America, joined Dec 2005, 2526 posts, RR: 3 Reply 11, posted (2 years 9 months 6 days 16 hours ago) and read 10302 times:
Quoting FlyASAGuy2005 (Reply 10): You said it was all white? Is it possible it was a ferry fight up to Alaska for a Horizon repositioning? (stops on the way of course).
Ah, good point. Very possibly. Another theory of mine was maybe some kind of flight test. The plane had a heading of about 280 (straight out towards the ocean) and kept that way for about as long as I could see it.
Guess I'll never know for sure.
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as739x From United States of America, joined Apr 2003, 5821 posts, RR: 23 Reply 12, posted (2 years 9 months 6 days 15 hours ago) and read 10127 times:
The Q400's do not operate in Alaska. Also, from the PDX area it would not be on a west heading (280) if going to Alaska. It would be heading northerly.
I'd have to guess some sort of test flightas that does seem weird seeing a Q400 on that heading and altitude.
"Some pilots avoid storm cells and some play connect the dots!"
cschleic From United States of America, joined Feb 2002, 1033 posts, RR: 0 Reply 13, posted (2 years 9 months 6 days 15 hours ago) and read 10054 times:
Due to the airshow at Hillsboro this weekend, traffic taking off to the west from PDX has to be routed further west than usual before heading south (if it's going that way), rather than turning south over the Hillsboro area as usual, so it would have been higher and heading westerly this time.
MidEx216 From United States of America, joined Jun 2005, 651 posts, RR: 4 Reply 14, posted (2 years 9 months 6 days 15 hours ago) and read 10054 times:
Quoting LN-KGL (Reply 9): Contrails you even can get on the ground provided the right weather conditions.
That statement is true, however I have to be picky; what you showed in the pictures are not contrails. Those are vortices. Those are a matter of pressure more than temperature (though both play a part).
as739x From United States of America, joined Apr 2003, 5821 posts, RR: 23 Reply 15, posted (2 years 9 months 6 days 15 hours ago) and read 10012 times:
25K is the passenger restricted altitude due to O2 requirments. There is options on the a/c for a 27K and I believe that aircraft can go into the 30K's range with a crew onboard doing a test flight. Why would they, who knows!
"Some pilots avoid storm cells and some play connect the dots!"
tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 16, posted (2 years 9 months 6 days 14 hours ago) and read 9957 times:
Quoting LN-KGL (Reply 9): Contrails you even can get on the ground provided the right weather conditions.
The local pressure changes around the propeller wings makes the water in the air condensate on humid days.
Technically, that wouldn't be a contrail. The mist you get around prop tips and wing vortices is extremely transient because it's caused by the local pressure drop...as soon as the surface moves away it disappears and no water is being added to the atmosphere.
A contrail is water being dumped by the engine condensing out and forming a cloud...it persists much longer because it's stable in the air independent of pressure and will persist as long as it takes for the water to switch back to vapour.
Highflier92660 From United States of America, joined Apr 2004, 594 posts, RR: 0 Reply 18, posted (2 years 9 months 6 days 14 hours ago) and read 9492 times:
As CBPhoto said, the Horizon Q400s are only certified to 25,000 ft. With individual drop-down passenger masks the aircraft would be certified to 27,000 ft.
Here is a video from circa 1950 showing the Boeing 377 Stratocruiser flying at the same relatively low altitude with a contrail. The phenomena is a result of moisture content in the cold air and some particulate matter in the exhaust. Here is a contrail from an aircraft equipped with P&W R-4360 recip engines. http://www.youtube.com/watch?v=7Fwp9Vheh8E
bartonsayswhat From Canada, joined Oct 2007, 434 posts, RR: 0 Reply 20, posted (2 years 9 months 6 days 10 hours ago) and read 6828 times:
It could have been a delivery flight to QantasLink or a South Asian operator. We had a delivery flight stop in YYJ last year and it departed striaght to HNL the next morning. Might explain why it was headed out to sea.
tharanga From United States of America, joined Apr 2009, 1778 posts, RR: 1 Reply 21, posted (2 years 9 months 6 days 10 hours ago) and read 6744 times:
Quoting bartonsayswhat (Reply 20): It could have been a delivery flight to QantasLink or a South Asian operator. We had a delivery flight stop in YYJ last year and it departed striaght to HNL the next morning. Might explain why it was headed out to sea.
The OP must have been quite sharp-eyed, and lucky with the timing, if that's the answer to the puzzle.
KPDX From United States of America, joined Dec 2005, 2526 posts, RR: 3 Reply 22, posted (2 years 9 months 6 days 9 hours ago) and read 6036 times:
Quoting bartonsayswhat (Reply 20): It could have been a delivery flight to QantasLink or a South Asian operator. We had a delivery flight stop in YYJ last year and it departed striaght to HNL the next morning. Might explain why it was headed out to sea.
That is exactly the first thought that came to my head. How cool would that be.
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T prop From United States of America, joined Apr 2001, 996 posts, RR: 1 Reply 24, posted (2 years 9 months 6 days 8 hours ago) and read 5074 times:
Quoting as739x (Reply 15): 25K is the passenger restricted altitude due to O2 requirments. There is options on the a/c for a 27K and I believe that aircraft can go into the 30K's range with a crew onboard doing a test flight. Why would they, who knows!
Think of the fuel flow... So what use would an aircraft be that can loiter for long periods of time over an area virtually unseen or heard?
25 AviationAddict: Must be Horizon's new PDX-ICN direct service!
27 whiteguy: Don't thinks its a QX Q400. Aren't their engines dark brown/black on the bottom?
28 SJC4Me: UBG and BTG VOR's are located in the Portland vicinity and both are on the Olympia Six arrival into SEA. Could have been a regular QXE SEA arrival.
29 KPDX: Hm possibly, but I looked on Flightaware for SEA arrivals around the time I saw it Saturday and nothing matched when it came to flightpath and timing
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