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Robert99

727 TAKE-OFF CLIMB PERFORMANCE

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377, georger, airtwardo, anyone else. Do you have information that can be used to estimate the climb TIME of the 727 from sea level to 10,000 feet in a standard atmosphere and in the landing gear, flap, leading edge devices, gross weight, etc., configuration that NWA had on take-off?

Assume a sea level take-off and a continuous straight ahead climb to 10,000 feet. Ignore the fact that NWA 305 leveled off at 7000 feet for a minute or two.

Just the climb time please.

Robert

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I flew NWA 727s for 14 years. One day I timed a takeoff from brake release to flap retraction at 1,000' and on that day it took 2:15. Once the plane is cleaned up I'm sure you could easily maintain a 3,000 fpm rate to 10,000' so my estimate is 5:15ish.

My best ever (civilian) time to climb was in an empty 757-300 where we went from brake release to level at FL 390 in 13 minutes. That was fun.

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4 to 7 minutes depending on weight.

Info from pilot who flew em forever and retired the AMR fleet.
It's called the Hillbilly Hop N Pop dude.
If you're gonna be stupid, you better be tough.
That's fucked up. Watermelons do not grow on trees! ~Skymama

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well we could actually SEE the altimeter needle climbing !!.. like it was doing double time.....
following take off,,,
during a jump from the 727 @ the WFFC,, Quincy Illinois...
it was Aug. 10th 1994
i've never been able to witness the undeniable MOVEMENT
of the needle... while still INside an aircraft , since....
B|
jmy

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Thanks to Meux and Buff for the information. And here I go again. What follows below is derived from the best of Hammer and Tong Engineering, creative cross-plotting of questionable data, and other advanced techniques that I came across in my days as a practicing Aeronautical Engineer. So you have been warned!

The only time data that can be reasonably accurate is that in the ATC transcripts related to NWA 305. I used the four times that also specified altitudes during the initial take-off and climb to 10,000 feet. Those times were plotted against altitude and the resulting manipulations resulted in a projected take-off time of 7:34 PM PST, as opposed to Sluggo's estimate of 7:33 and the FBI's estimate of 7:36.
In addition, the winds aloft were estimated from the chart that depicted the original guess as to Cooper's landing zone.

All of this resulted in a three segment climb to 10,000 feet with the entire climb being flown at 160 KIAS. First, the climb from the Seattle airport to 7000 feet would take 6.5 minutes and cover 16 nautical miles. The aircraft would maintain 7000 feet for 7 minutes and cover 18.5 NM. Then the climb on up to 10,000 feet would require 6 minutes and cover another 16 NM. The total time from wheels off to 10,000 feet would be 19.5 minutes and cover 50.5 NM.

The end result of the above is that the climb to 7000 feet was at a rate of only about 1000 feet per minute and the climb from 7000 to 10,000 feet was at a rate of only about 500 FPM. The aircraft reported "leveling at 10,000" at about 7:53.6 PM which would be the time that it was 50.5 NM down V23. This point is about 13.5 NM north of the Malay Intersection and several NM south of the point that is labeled "1954" on the FBI charts.

The distance from the 50.5 NM point to the PDX (now BTG) VORTAC is 54.5 NM and the aircraft would arrive at PDX, assuming it stayed on the centerline of V23 for the entire distance, at 8:11.8 PM PST. If this estimate is correct, then Cooper jumped within 3 NM of the PDX VORTAC assuming a jump during the time the aircraft clock showed 8:11 and assuming the clock was correct to begin with.

The above was done on a conservative basis (i.e., tried to slow the airplane down) insofar as possible. There is no basis for assuming that the winds aloft were ever greater than about 30 knots at 10,000 feet, regardless of what Captain Bohan reported at 14,000 feet.

While I understand the claim that Cooper jumped into a rainstorm, the weather was generally reported as good with haze and fog south of Portland and generally higher atmospheric pressure south of Seattle. Haze and fog are generally associated with relatively stable weather systems and low surface winds.

To make a full disclosure here, I do not think the airliner overflew the PDX VORTAC but stayed some distance west of it to avoid flying over Portland proper. If this assumption is correct, then Cooper probably was quite near Tena Bar when he jumped.

I understand that there are some strongly held opinions contradicting the above. But your comments are welcome and I look forward to seeing them.

Robert Nicholson

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I'd like to share the following data from https://www.ncdc.noaa.gov/data-access/weather-balloon/integrated-global-radiosonde-archive: relating to wind speed and direction in the Seattle area in late November and early December 1971. SEATAC: wind on 11.24.1971 at 4000 feet: 210 degrees, 34.0 knots; no data for levels above 4000 feet; wind on 12.02.1971 at 9000 feet: 190 degrees, 47.0 knots. GRAY AAF, 47.13N  -122.6W: wind on 11.23.1971 at 9000 feet: 230 degrees, 38.0 knots; no data for 11.24.1971; wind on 11.26.1971 at 9000 feet: 230 degrees, 28.0 knots.

711124 72793 weather aloft.xlsx

71123 74207 weather aloft.xlsx

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On 8/18/2019 at 10:24 PM, DFS346 said:

Attached is a plot of airway V-23 and the FBI estimate of the flight path of NWA305, between Seattle and Portland, superimposed on the current FAA aeronautical charts.

 

Here's an improved version of the map, including the flight path south of Portland, as estimated by the FBI.

NWA305 and V-23 v04.jpg

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