Wednesday, October 9, 2013

Static Line Failure? Altimeter Malfunctioning? No Problemo!

The weather is blowing sideways here in lovely San Diego, and I figured it would be a good time to update my blog with a review that I recently wrote regarding a watch I purchase.  Many of you will immediately wonder why I'm writing a review for a watch, since it is used fairly infrequently in the cockpit, and most airplanes com equipped with a clock.  My enthusiasm for writing this stems from the functions that this watch can perform.  Read below:

It would probably fly off if I left it here...
I have been scouring the interwebs for a new watch, and finally landed on a watch that can hold its own inside the cockpit. I have been aching to get my hands on this bad boy since I first saw it a few months back on the Citizen website.

My day job these days is to fly a large banner around San Diego (those of you who live here will probably have seen me at some point ---> GIECO) and wanted this watch for something to fiddle with while flying (no joke, it can get boring). I picked this particular on up from Electronic Bay .com (to quote an idol of mine: Ron Swanson) on Monday. I had been checking The site every few hours for a black example to pop up, and when I saw one for $592, I snapped it up ASAP. The seller has since raised the price to $750 or so, which makes me think I may have gotten this one during a mistake on their part.

It arrived this morning (long wait for priority shipping LA to San Diego), and my initial feeling when I boxing was the weight, or lack thereof. I have a Citizen Scuba Fin, which is my "do-everything" basher watch, and this feels significantly lighter. Another shocker for me is the strap. I had been planning on replacing it very soon after taking ownership, but I think I will keep it around. It is so soft, and holds very securely. Another is the quality of the crowns, which compared to my only other screw down crown Citizen I own (Scuba Fin) is worlds better. They unscrew smoothly and are spring loaded to slightly pop out a bit, so you're not constantly rubbing the threads when adjusting the watch. I have only been ogling the watch for a few hours, but thought that if anyone else out on the forum was as obsessed as I have been about getting this as I have been...they would want to read a bit about it too! I will update this post tomorrow after another flight, where I will video the altimeter on the watch next to the planes altimeter to get an idea of the refresh rate, accuracy and smoothness of the reading. Hope to have the video posted tomorrow evening or maybe Monday afternoon.

On the money.
Sunday I had a flight and got a chance to stack up the mighty Promaster Altichron BN5035-02F against the altimeter in my Piper Pawnee PA-25 Banner tow rig. First let me begin by explaining the simple function of a "kollsman window". The kollsman window on the altimeter is the indicator for the small adjustment to atmospheric pressure changes that frequently happen while flying. I typically fly for 4 hours at a time, and will cover quite an array of landscapes, these changes (over ocean, desert, city etc) will often come with a barometric pressure change. Every time i transition from one airspace center to another, the Air Traffic Controller I speak to will give me the current altimiter setting for that area. like stated earlier, this number will change throughout the flight, and allows my altimeter to be calibrated for the airmass I am traveling through at the moment. While on the ground, if the altimeter is set to the current barometric pressure the altimeter will indicate the elevation of the ground that you are resting on above MSL (mean sea level = height above the average altitude of the ocean).

Ill pause to let that soak in. Its not too complicated, but will help you understand some info about the watch below.

The watch has no such kollsman window . BUT.....never fear! It is a good thing! instead of having to track down the barometric pressure while on your hike, or out on the road you simply have to know your current elevation, which is readily available on maps, road signs and the nearest ol' timer. Setting this value into the watch will ultimately adjust the watch to non-standard pressure and you will have an accurate reading UNTIL you move into another airmass of a different pressure. This change can happen throughout the day if: a front passes, sun goes down, wind speed changes, etc.

After setting my watch the the field elevation of my airport and setting the aircraft's altimeter to the current barometric pressure, the indicated altitudes lined up perfect! Who would have thought! In the video below, differences in the indicated altitudes between the watch and the aircraft are NOT the fault of the watch. I had changed the value in the kollsman window several times, and did no adjusting to the watch during the flight. I just wanted to give you all a lengthy explanation as to why there was a small (25-50' variation) in the indicated altitudes in the video. this was no fault of the watch at all, in fact I was nothing less than amazed at the speed and accuracy of the readings.

If I wanted to I could have simply adjusted the watch's altitude to the known altitude given by the altimeter, and it would have essentially given the same result as setting the watch on the ground, I was just feeling lazy.

Video below of the 2 altitude instruments side by side for a comparison during some ascents and descents in the aircraft. Let me know what you think!

PS I understand this isn't a typical watch review, however I wanted to share my experience with the altimeter function. I was skeptical of its capabilities at the beginning, however I walk away amazed, and wanted to share that. Also my job allows me to be able to test its performance in a way not many can, so I thought that would be valuable info to some. Thanks for reading!




1 comment:

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    ReplyDelete