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Possible CTLS down, Breezy Point, NY


paul m

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The 100' was on a flight the day prior to the accident in daylight.  On the night of the accident he was flying at 1000 feet (fairly constant) for the whole flight right up until the problem (whatever it may have been) caused him to turn out to sea and then descend into the ocean.

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Very sad indeed on the other hand I'm not sure for you guys in the US but in Australia my dynon skyview ADSB transponder transmit its altitude in ft corrected to 1013 hPa and that is the altitude displayed on flightradar24

So the 100ft altitude he was flying at mite not be actual altitude.

Good point. While he would still have been quite low. I know the altitude that displays on my transponder is corrected, and it is the altitude that ACT sees. This is most likely also the altitude that was plotted for the flight.

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Good point. While he would still have been quite low. I know the altitude that displays on my transponder is corrected, and it is the altitude that ACT sees.

 

Traditionally, transponders display Pressure Altitude, uncorrected for altimeter setting, on their displays, since that is what is transmitted.

 

The receiving facility adjusts that Pressure Altitude readout to roughly msl via an altimeter setting on their end.

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Traditionally, transponders display Pressure Altitude, uncorrected for altimeter setting, on their displays, since that is what is transmitted.

 

The receiving facility adjusts that Pressure Altitude readout to roughly msl via an altimeter setting on their end.

 

I understand that, but does the tracking like they are using to say he was at 100 feet use the raw data (pressure altitude) or the data corrected to MSL? Depending on the conditions the raw data could be off by a few hundred feet.

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All but the last two data points are ADS-B Out received by FlightAware tracking systems so the altitude is GPS.  The last two are Tracon and look to be a little off.  The second to last reading (Tracon) has the plane at 800 and prior ADS-B had him at 700 and descending over a 15 second period.  Doing a little data smoothing would imply the plane was likely to be at 500 vs. 700.  This could imply that his altimeter was set such that he was displaying higher than he actually was by a couple hundred feet.

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All but the last two data points are ADS-B Out received by FlightAware tracking systems so the altitude is GPS.  The last two are Tracon and look to be a little off.  The second to last reading (Tracon) has the plane at 800 and prior ADS-B had him at 700 and descending over a 15 second period.  Doing a little data smoothing would imply the plane was likely to be at 500 vs. 700.  This could imply that his altimeter was set such that he was displaying higher than he actually was by a couple hundred feet.

 

If GPS then the altitude is True Altitude.  Tracon should be using radar based on his Mode C or S transponder altitude encoder.   If he was 700 or 800 the Kohlsman would have had to be substantially off to get a 700 foot error.

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If GPS then the altitude is True Altitude.

 

GPS can have much more error in vertical (altitude) positioning than in horizontal (Lat/Long) position, due to the ellipsoid shape of the GPS satellite cluster..  I would not trust GPS altitude as the "true" altitude.  An accurate altimeter with a correct local pressure setting is still the "gold standard" of altitude measurement.

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GPS can have much more error in vertical (altitude) positioning than in horizontal (Lat/Long) position, due to the ellipsoid shape of the GPS satellite cluster..  I would not trust GPS altitude as the "true" altitude.  An accurate altimeter with a correct local pressure setting is still the "gold standard" of altitude measurement.

 

When you study for your instrument rating you'll learn that the best (an likely only reliable way) to determine True Altitude is to refer to what the GPS receiver indicates (GPS-MSL).  

 

When flying in the mountains (or in this case over water an night) you better have a pretty bullet proof way to determine True Altitude.  Depending on your round gauge and an aneroid wafer and a static pressure sensor and some distant and not very timely AWOS altimeter number is tenuous at best, especially if you don't reset your Kohlsman.

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Andy -- the altitude you see on your Garmin (and most other aviation GPS systems) has been corrected. Specially,  GPS altitude is based on the WGS-84 ellipsoid model (sometimes called HAE) which can be several hundred feet off depending on the distance from the poles.  To account for this error many GPS units map this ellipsoid to a more refined geoid model (GEOID12A is the latest, I think) which is highly accurate.  With a WAAS GPS your true altitude will be within a couple meters of what your GPS displays.  Altimeters have an allowable error of 200 ft.  And temperature deviation from ISA further erodes the accuracy by 4% for each 10C delta (from ISA).

 

In short, the GPS will be very close to your true position and altitude while your altimeter will be 'accurate' for being in the system (as CT noted) .

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  • 2 weeks later...

An update about the preliminary report.  

 

http://www.nbcnewyork.com/news/local/Plane-Down-Breezy-Point-Ocean-Death-Brad-McGee-Navy-Commander--352195851.html

 

Excerpt from the NBC NY Story:

 

"According to the preliminary NTSB report, no noticeable mechanical issue was detected. The aircraft had been topped off with fuel prior to departure. All major components of the aircraft were recovered from the water, and authorities determined flight control had not been affected.  The propeller remained attached to the engine. All three blades were fractured about midspan from the propeller hub. Spark plugs exhibited normal wear. The parachute was found separated from the airplane and had been partially deployed.  The preliminary investigation did not reveal a possible cause of the crash. A final NTSB report on the crash is due out in about a year. According to plane flight records obtained by NBC 4 New York, the same pilot made a hard landing in the aircraft two years ago. The FAA found it was due to pilot error."

 

Here is the actual preliminary report from the NTSB:

 

http://ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20151104X30605&key=1

 

NTSB Identification: ERA16FA031
14 CFR Part 91: General Aviation
Accident occurred Wednesday, November 04, 2015 in Queens, NY
Aircraft: FLIGHT DESIGN GMBH CTLS, registration: N622BT
Injuries: 1 Fatal.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

On November 4, 2015, at 1933 eastern standard time, a Flight Design GMBH CTLS, light-sport airplane, N622BT, was destroyed after it impacted the Atlantic Ocean near Queens, New York. The private pilot was fatally injured. Night visual meteorological conditions prevailed and no flight plan was filed for the personal flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. The flight originated from Northeast Philadelphia Airport (PNE), Philadelphia, Pennsylvania, about 1900, with the intended destination of Portsmouth International Airport at Pease (PSM), Portsmouth, New Hampshire.

According to airport personnel at the departure airport, the airplane was "topped off" with fuel prior to departure. A fuel receipt, time stamped on the day of the accident around 1840, indicated 17 gallons of 100LL aviation fuel was added to the airplane.

According to witnesses, they watched as the airplane descended into the ocean. One eyewitness described the descent angle as an approximate 45-degree nose down attitude into the water. Also, the witness stated that he heard an "explosion" a short time later. In addition, a pilot, who responded to the search for the wreckage, noted that it was "pitch black" out over the water.

A postaccident examination of the airplane revealed that all major components were recovered from the water. In addition, flight control continuity was confirmed from the cockpit controls to all flight control surfaces through tensile overload breaks and cuts facilitated for recovery.

The propeller remained attached to the engine. All three blades were fractured about midspan from the propeller hub. The top spark plugs associated with cylinder nos. 1 and 3 and the bottom spark plugs, associated with cylinder nos. 2 and 4 were removed. The spark plugs were light grey in color, and exhibited normal wear. The propeller was rotated by hand and thumb compression was confirmed on all cylinders. The rocker box covers were removed in order to visually confirm valve train and crankshaft continuity throughout the engine.

The ballistic recovery system parachute was recovered. The parachute was found separated from the airplane and was partially deployed. The rocket motor was discharged. The ballistic recovery system handle was not recovered from the water.
 
 

 

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  • 3 weeks later...

Sunset was 3 hours before. Moon rise was 3 hours later. Except for the city lights and his nav lights it was dead dark. I'm surprised the folks on the land could tell what they were looking at.

The sound of chute deployment, or crash, is gong to reach them late due to the difference between the speed of light and sound - a little more that a second for every quarter mile they are away.

The chute may have deployed on impact or it may have been deployed shortly before.

Mike Koerner 

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  • 1 year later...

The NTSB released its final report on this accident (attached).  Sharing for others to learn from.  Spatial disorientation flying at low altitude over the water at night.  Brad was an accomplished man and an all around good guy.  It should remind us that ours is a license to continuously learn.

NTSB Final N622BT.pdf

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