What caused this Cessna 310b to crash at my local airport?

[scott.carpenter4491]

As some of you may know, two weeks ago a Cessna 310b crashed while taking off from a small, one-runway airport in Columbia, California, a small town near the base of the Sierra Nevadas. All four on board died in a resulting fire.

I'm a reporter at that town's local newspaper, the Union Democrat, and our paper was the first to report on the crash and the deaths. Coverage from the Associated Press and CBS Sacramento soon followed.

Can any experienced pilots or mechanics here weigh in on typical or likely explanations for such a crash -- or at least factors that would have proved crucial?

The National Traffic Safety Board has since concluded its week-long investigation -- but it isn't likely to release its report on what it believes caused the crash for another 6-8 months. Its next step is to ship the plane's two engines to their manufacturer, Continental Motors, in Alabama for further inspection.

What we know is as follows: Shortly after 4 p.m. on July 24, a 1959 Cessna 310b, with four people onboard, veered from the airport's only paved runway (runway 17) while attempting to take off. (Initial reports said it was landing.) By the time authorities arrived, the plane was engulfed in flames and lay on its belly in a patch of low grass some two or three dozen yards east of the runway. It came to rest roughly parallel with or just beyond the point on the runway where a plane of that size typically rotates.

The four victims -- two roughly middle-aged couples -- were burned so badly that forensic identification required examining dental records.

Conditions were good. It was a near-cloudless day with normal wind conditions.

The pilot, Dan Kreutzfeldt, was a 43-year-old experienced career transport pilot with NetJets.

Thanks for your insights. I am not asking for speculation, but for typical causes of crashes resembling the one here.

Scott Carpenter

[Newforest2]

https://aviation-safety.net/wikibase/wiki.php?id=188902

The ASN report

[aterpster]

Here is the NTSB preliminary report. It happened on July 27, not 24.

http://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20160727X20105&key=1

Based on the information in this preliminary I would speculate they had an engine failure just after becoming airborne. Most light twins won't climb in such circumstances. Many pilots, in such awful circumstances, try to keep it flying. Speed decays, until the yaw caused by the good engine causes the airplane to lose directional control, all the while not climbing. Airplanes at NetJet don't have this problem. They are certified under the much stricter FAA Part 25 rules. Part 25 airplanes can maintain control and continue to climb with the loss of one engine just after becoming airborne.

Then again, this accident could have been a jammed flight control. Possible, but less likely than an engine failure. Because light airplanes lack flight recorders, the investigators have to examine the engines in great detail. Same with the flight controls, but that can become problematic after an intense fire.

[+TSRA]

Then again it could have been a heart attack, or flight control failure, or engine failure, or, or, or - there is not enough information to draw any conclusions or speculations and it is far too early to compare this to any other crash based on the information provided by the NTSB.

The fact they are looking at the engines means nothing at such an early stage, even though an engine failure with speed decay below VMCA is a probable outcome.

I have to ask the OP whether he is willing to independently verify the credentials of any responses he gets prior to publication considering he is asking on a forum where Microsoft flight simulator users have claimed to be "experienced pilots" for similar posts in the past.

[pattern_is_full]

I agree with aterpster. But to unpack that a bit more for a journalist:

When a small twin-engine plane has an engine failure, not only does it lose half its power, but the remaining power is now asymmetric, since the good engine is out there on one wing, to one side or the other of the center of the aircraft.

Like a slow-motion catherine-wheel, the asymmetric thrust tries to push the plane in a circle, or "yaw," towards the failed engine, as aterpster says. In addition, the propeller blade on the failed engine is now, for all practical purposes, just a big aluminum board dragging in the slipstream, adding to the yaw force, and also degrading the overall ability to maintain flying speed.

Bizjets with engines (usually) on the fuselage near the tail, still produce asymmetric thrust if one engine fails, but not as much as a plane with engines way out on the wings and far from the centerline. A small light piston-engine prop twin is actually trickier to handle if an engine fails.

Learning to handle an engine failure, and maintain control with the abnormal aerodynamics in a twin, is the core of training for, and receiving, a "multi-engine" rating.

The pilot has to be very fast off the mark in making several adjustments to the controls: identifying which engine has failed (fairly easy with a C310 - the engines are right outside the windows); rudder away from the failed engine to counteract the yaw; "feathering" the failed engine's propeller blades so that they are twisted thin-edge-on to the slipstream for minimum drag; some aileron (roll or bank) away from the failed engine. While also maintaining flying speed with half-power, yet not descending into the ground. And dealing with the "startle" factor - "What the heck just happened!?"
______________

Other factors, not specific to twins, that would degrade airplane performance and reduce the margins with (or without) an engine failure:

Elevation - the air in Columbia (elev. 2000+ feet) is less dense than sea level. Less air for the engines to breathe (less power), less air to lift the wings. That reduces the margins for error in the case of some other problem.

Density altitude - hot air is even thinner. If it was a hot July afternoon (80°+), the effective elevation at Columbia (air available as above for flying) might be as much as 4000 feet. Another bite out of the margin for error.

Weight - 4 people in an C310 is not excessive by itself. But if there was a full fuel load and degraded performance due to air temperature and elevation....

Ground effect - within a wing's length of the ground, a cushion of lift develops between a wing and the ground. It is not at all unknown for overloaded or underperforming aircraft to lift off from the runway successfully with that extra "ground" lift - at a speed that is not enough to continue flying "out of ground effect." Result - you are off the ground, but unable to climb beyond 10s of feet, unless you can continue to accelerate (which may require a slight descent to pick up speed).

One can probably assume a jet pilot understood all of those very well, and did the appropriate "reduced performance" calculations that he does every day in his professional work.

But he might have been close enough to the safe margins that a failed engine put him outside the envelope.

[aterpster]

If the engine failed at 40 feet, the only option was to reduce the power on the remaining engine (not to idle, though), keep the yaw to a minimum, and plant it back on to whatever runway was remaining.

I recommended to the reporter that he find a current, and experienced light airplane multi-engine CFI, preferably one with 310 time.

[john_tullamarine]

When a small twin-engine plane has an engine failure, not only does it lose half its power

Ah, but the devil is in the detail. What the pilot needs is spare thrust .. and that decreases by, say, 70-80 percent.

While most of us love the dear old 310, they aren't sparkling when it comes to OEI .. hence .. aterpster's sensible suggestion to plant it back on to whatever runway was remaining.

[aterpster]

J.T.

Ah, but the devil is in the detail. What the pilot needs is spare thrust .. and that decreases by, say, 70-80 percent.

And, a very big detail indeed, close to the ground, with failed engine not feathered, and best single-engine rate of climb (blue line) far from being achieved.

My favorite characterization of the typical Part 23 piston when is that it is a "single-engine" airplane with distributed power plants. If one of those power plants fails on takeoff (or anywhere close to the ground...low and slow) you've lost perhaps as much as 85 to 90 % of your required thrust.

The old Piper Apache when losing an engine at cruise was going for a landing. Assuming a proper clean up you probably could maintain the glide-slope on an ILS, provided you kept the landing gear up until short final.

[Tinstaafl]

That's how I taught Part 23 twins: The 'single' engine was split into two packages, somewhat like a V8 engine. A failure would most likely affect only a single package, leaving the other half still running.

Just like a V8 with one dead bank. Might be just enough power to drive along a level road (if it was a big enough capacity V8), but probably not enough to go uphill, nor enough to tow a heavy trailer or with a the handbrake on. Particularly if in the mountains. In the Part 23 twin, maybe enough to maintain altitude (if a big enough twin - think >6000lb etc), but probably not enough to climb. Bad luck if heavy, draggy, high density altitude.

[Amadis of Gaul]

Unfortunately, Scott, with the limited available information, all one can do is speculate.