A summary of the NTSB's findings is here:
http://www.planeandpilotmag.com/content/2004/apr/ntsb_wellstone.htmlThe NTSB has released its final report on the October 25, 2002, accident in which U.S. Senator Paul Wellstone of Minnesota and seven others were killed at Eveleth, Minn. The twin-engine turboprop King Air A100 didn't have a cockpit voice recorder, so there was no possibility of investigators learning what the pilot and copilot might have said to each other about the way things were progressing during the VOR approach to Eveleth. Investigators had to rely on other things to figure out what caused the airplane to experience an aerodynamic stall at a critically low altitude. In reconstructing the accident scenario, investigators used radar data, ATC audiotapes, aircraft performance numbers, interviews and a large body of experience derived from investigating other accidents.
Investigators found that the flight crew failed to recognize two things that should've prompted an immediate go-around during the VOR approach to runway 27 into Eveleth-Virginia Municipal Airport (EVM): low airspeed and full needle deflection on the CDI. The flight crew should've been flying at no less than 120 knots. The airplane operator's procedures called for a non-precision approach to be abandoned if the airspeed deviated by more than 10 knots below 500 feet AGL. The airspeed remained below the required speed for about 50 seconds, reaching a low of about 76 knots. Procedures also called for an approach to be abandoned with a CDI deflection of more than three-quarters scale.
(snip)
The copilot acknowledged the instruction. Radar data indicate that the airplane began turning left while maintaining 3,500 feet and slowing through about 164 KCAS. Almost immediately after the airplane began its left turn, it overshot the approach course and traveled for almost one mile north of the course as it continued the turn until it established a ground track of about 262 degrees.
(snip)
At 10:20:06, as the airplane passed through the approach course about five miles east of the runway 27 threshold, a slight right turn was initiated and the airplane's airspeed and vertical speed decreased. The airplane established a ground track of about 269 degrees and maintained this track until the end of the radar data at 10:21:42.*****
The NTSB concluded that the probable cause of the Wellstone's crash was pilot error. Icing was ruled out as a contributing factor, and no explanation was advanced for how or why the plane drifted over 7 degrees off course as if got NEARER to the VOR (navigational radio beacon) for least 90 seconds until it finally veered sharply to the left and steeply plummeted to the ground over a mile south of its authorized approach.
This is the critical occurrence that no one (including the NTSB) who has argued that the crash was due to pilot error has ever addressed. How did the plane somehow drift or turn well over a mile off course -- a huge navigational error over a period of at least 90 seconds -- during its final instrument approach? Note that the standard King Air procedure for this approach is to use the autopilot to steer the plane toward the VOR beacon (for details, see "Non-precision approach" at:
http://www.navfltsm.addr.com/vor-appr.htm ).
So even though asserting just this much already obviously strains credulity to impossible levels, it's not enough to simply posit that both Conry and Guess managed to ignore the fact that the CDI needle was pegged all the way to the left for over 90 seconds while they somehow managed not to notice that they had slowed more than 60 mph below the recommended approach speed until the stall warning horn was blaring in their ears at which time they made the cardinal sin of attempting too sharp of a power turn at too low of an altitude. This "explanation" -- such at it is -- entirely begs the question of how the King Air A-100's autopilot, an extremely reliable piece of equipment that another pilot confirmed was functioning normally just the day before, managed to steer the plane so far off course.
If we assume that the crash was accidental, the only possibilities are:
1) The pilots decided the make the approach manually AND while attempting this unexplained and dangerous manual approach, neither pilot ever even glanced in the direction of the CDI needle, which would have been their only directional guidance in overcast conditions (all while mysteriously and fatally slowing almost to stall speed, of course). In addition, note that the NTSB summary of interviews (
http://www.startribune.com/style/news/politics/wellstone/ntsb/252886.pdf ) states, "
When Conroy flew, he would always fly with the autopilot engaged."
2) The pilots somehow managed to engage the autopilot on the wrong target. But in this case another question is begged -- namely, what other possible target could have given them a remotely reasonable DME (Distance Measuring Equipment) reading? But this option -- like so much about this crash -- argues for foul play. (For example:
http://news.bbc.co.uk/1/hi/world/africa/96025.stm )
Of course, if we don't assume that Wellstone's crash was accidental, then we can choose from a myriad of reasonable explanations for this otherwise virtually unexplainable chain of events. Here is just one scenario that I find entirely plausible:
1) A "service vehicle" equipped with both a decoy VOR beacon with a stronger signal than Eveleth Airport's VOR and an Active Denial System weapon (see:
http://boston.bizjournals.com/boston/stories/2004/08/02/daily40.html ) is placed 1-2 miles south of the airport, probably off road, and nearly the same distance from the final VOR approach turn as the airport's actual VOR beacon (so that the DME would read as expected on and subsequent to the approach turn).
2) After the plane finishes its final approach orientation and the Duluth ATC signs off, the overriding VOR signal is switched on. Note that Eveleth Airport is seldom used, and that any pilots further than 30 miles away who were using Eveleth's VOR for navigation purposes (if there were any) wouldn't even notice the tiny change in needle (and perhaps course) deflection that homing in the the new overriding target would entail. Further note the "on again/off again" cover story about Eveleth's VOR being "slightly out of tolerance" (see:
http://news.minnesota.publicradio.org/features/2003/03/03_zdechlikm_wellstone ), just in case somebody DID notice any temporary problem or discrepancy in navigation.
3) In the cloudy, overcast conditions, Wellstone's pilots would be basically relying on autopilot to guide the plane horizontally to the VOR -- in this case the false, overriding decoy VOR -- resulting in the plane being drawn off course in the exact manner the radar returns demonstrate.
4) When the plane is drawn off course close enough to get in the range of the ADS weapon (currently classified but almost certainly 1/2 a mile), the cockpit area is zapped -- resulting in an effectively pilotless plane. Of course, many other weapons could have been used, but this one has the expository advantage of recently appearing in several high profile, mainstream news stories.
5) The overriding decoy VOR is then switched off, causing the plane's instruments to reorient to Eveleth Airport's real VOR. This last minute reorientation would cause the still engaged autopilot to attempt a sharp right turn -- "crabbing to the right" in the words of one eyewitness (
http://www.twincities.com/mld/pioneerpress/4376969.htm -- exacerbating the loss of control of the already pilotless plane.
6) After the plane crashes, someone would presumably make sure the cockpit instruments were consumed in flames -- just on the remote chance that a serious, full inquiry were to be demanded -- as the "cable TV/power company/telephone service vehicle" makes its escape from the scene of the crime.
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