Tesla Cessna 310 Crash at East Palo Alto: The Paradox of the Twin
One might think that a twin-engine aircraft is safer than a single-engine aircraft. After all, if one engine fails, you still have the other to bring you home safely. That's the whole point of the second engine, right?
If one of the twin engines fails in cruise flight, maybe that's true. But if it quits right after takeoff, the twin can be extremely difficult to handle. When the aircraft's landing gear is down, its flaps set, and its airspeed just above the minimum flying speed, the asymetric thrust generated by the operating engine can flip the aircraft onto its back and out of control. A "Vmc roll", as it is called, is
almost always fatal. When an engine quits during the critical takeoff phase of flight, a pilot -- even one who does everything right -- may not be able to land the twin-engine aircraft safely. Fog and a short runway (such as Palo Alto's) make matters only worse.
It's too early to tell, but it's possible that the Twin Cessna in which the T
esla employees were flying experienced an engine failure. First, a witness at Palo Alto Airport reported hearing the unmistakable thrumming sound of two engines as Cessna N5225J rolled down the runway. That was followed by what sounded like just one engine running, and then an impact.
Second, having flown out of Palo Alto many times, I know that Air Traffic Control instructs pilots flying on instruments to proceed straight out, then turn right to a heading of 060 degrees within one mile from the airport. (The airport was fogbound when N5225J took off, so the pilot would have been making an instrument departure.) But as depicted below, the aircraft crashed well left of the expected course. That's consistent with a loss of control following an engine failure on takeoff. 
Because it's so hard to fly a twin-engine aircraft after one of its engines fail, many pilots feel safer taking off in a single-engine aircraft. First of all, the chances of a single-engine aircraft experiencing an engine failure on takeoff is only half that of a twin. Second, if the single engine does fail, the aircraft can still be flown like a glider. Its heading is just as easy to control as if its engine were running normally. In this case, a landing straight ahead onto the mud flats, or even a right turn toward the water, might have been accomplished successfully in a single-engine aircraft. Either path would have provided a better chance of survival than the Twin Cessna's turn to the left.
February 20 Updates:
Tesla Crash: NTSB Probable Cause Investigation
Crash Likely Caused By Lethal Combination of Factors (Merc News)
SpotShotter seems to indicate both engines running.
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/02/18/BA6C1C3LSP.DTL&feed=rss.news
I have to disagree with a bit. As a multi-engine rated pilot, the engine failure at takeoff is the most serious condition. However, in the hands of a proficient pilot, it should not result in the crash as suffered in this accident. There is nothing that a single-engine aircraft could do that would not also be possible in the twin. However, the twin does have power and can, when flown properly and proficiently, continue flight to a safe altitude and proceed to a suitable controlled landing.
The some pilots prefer a single-engine is simple ignorance and superstition. I think it very rare for any experienced, rated, multi-engine pilot would think this at all. This is something that is oft-spouted from unqualified pilots and would-be pilots.
An unskilled pilot, or one without proficiency and currency in multi-engine operations, is probably more dangerous than he would be in a single engine aircraft. Handled improperly, any aircraft is dangerous.
We do not know what happened to this plane. It could have been anything from pilot disorientation (which happens to the best of us) to a health related incapacitation of the pilot, or some other mechanical emergency such as a failure of a control system.
I have to say, I am troubled by his departure in the reported conditions. I work in the area and declined to ride my motorcycle to work due the fog. Waiting a few hours led to a beautiful, sunny day with wonderful weather. Survival is about options and PAO's short runway and low visibility that morning left a lot fewer options in the event of an emergency than I am comfortable with.
Jim-
Thanks for the link. This information will be important. While an engine can fail without stopping cold, the recording nonetheless calls into question the report of the witness at the airport.
Normally, investigators rely on the condition of the propellors to determine if an engine was making power at impact. Blades bent forward indicates that the engine was indeed making power. That analysis, however, can be made only when the aircraft impacts the ground in a more or less controlled fashion -- not the case here.
larrysb you're fooling yourself. engine failure in a 310 at rotation with 3 aboard and a 2500 foot runway and you're toast. The weather doesn't matter, it's about aircraft weight and field length.
My preference for single engine aircraft is not based on "ignorance and superstition." 10% of all fatalities in single engine aircraft are due to engine failure. 25% of all fatalities in twin engine aircraft are due to engine failure. That says something about a twin's ability to fly on one engine. It costs about four times as much to insure a twin as it does a comparatively priced single. That says something too.
Rick, I have a very hard time believing weather wasn't a factor in this case, even if he did experience an engine failure. I've never flown out of PAO, but have departed other short fields in my 310Q, and even with 2 pax and a full load of fuel (just about every 310 has a different aux tank configuration, but let's assume ~900lbs of 100LL), she'll accelerate to blueline in that distance (if only just) and even climb dirty on one when departing from a sea level field. That wasn't a Seminole or Duchess he was flying yesterday. Also, notice that at least one of the mains is clearly stowed in the pictures from the scene, which makes the VMC roll theory even more unlikely in my opinion. Unless the problem turns out to have been control continuity, had he elected not to depart 0/0, he could have at least monitored his altitude AGL and had a say in where she "landed". I don't know, we can armchair this from a hundred different angles, and I've heard all the safety statistics comparing singles to twins, but when it's dark out or I'm in the soup and there's hard stuff below me, I'll take 2 fans every single time.
Looks like it was a nice a/c: http://www.airport-data.com/images/aircrafts/small/195/195397.jpg
Tragic on all counts...
I think maybe he had a gyro problem ...the runway there is 2400 ft he was heavy ,I flew a 310J its a runway hog very heavy on the controls and I had to always set the heading bug before takeoff . This guy was busy he took off in very low vis , I think they act had a ground stop in SJC ..he went anyway ...full power before brake release, pulled up as soon as the speed would allow, threw the gear up and kept the nose down to accelerate ,now the gyro sometimes when it is cold would lag ,in the plane I flew would act weird when I was flying in wet conditions..I have heard the recording of the crash and what I heard was two engines finding the same rpm ..a right turn after departure is where he should have been ...a gyro failure seems to be the only option if in fact both engines were runnin.
I think Mike's post is pretty accurate, with one small caveat. I have about 1000 hours in piston twins, and I've experienced 4 engine failures (but no accidents, thank goodness). I have a little bit of experience in this area. There is a brief period of time after takeoff where most piston twins cannot continue on one engine. In order to continue a climb on one engine in a piston twin you need 3 things: airspeed at or above blue line, gear up, and the prop feathered. Maybe a 421 with half fuel and no PAX could power through but an old 310 w/ 4 people and gas certainly wouldn't. The one thing I would add to Mike's post is that a piston twin pilot always has the option of reducing the power on the operating engine and making a forced landing. In case of a failure just after T/O and before satisfying the 3 killer items, that is the only option and no amount of proficiency will change the facts. If you can't accept that, you need to buy a single or a turbine but you can't safely fly a piston twin. My engine failures all happened in cruise so thankfully I never had to make that very hard decision. But I brief it on every single T/O and I believe it is the only way.
Scott - Four engine failures in 1000 hours. Yikes! That has to be some sort of record.
Thanks for the insight.
Mike
The Cessna 310 is designed with the same basic wing as the Cessna single engine line of 172, 180 and 210. It's the same wing jig and all aircraft share the same wing area of 175 sq.ft. The 310 wt. is 4990 gvw and the 180 wt. is 3,200 gvw. A twin pilot lands at 90 ias and the 180 at 65 ias. Military pilots who fly anything less than three engines have parachutes. A joke; however , a piston twin statistically is twice as likely to kill as a single. On 'You-Tube' there is a wing extension that is proving to add lift without drag and eliminate the stall/spin event . It is called the Hamilton/Nobias wing Diskette and is found at 007 wingman channel on 'You-Tube'.
First let me say how sorry I am for the tragic loss of the pilot and passengers.
Regarding the discussion about causes and should-haves, here is the preliminary NTSB report:
http://www.ntsb.gov/ntsb/brief.asp?ev_id=20100217X24906&key=1
Folks, the plane flew into power lines at 50ft AGL. The pilot must have been returning to the airport (debris path was SWerly) but was not aware of the terrain. The "aircraft's point of rest" above is misleading as it may make one imagine a northerly heading.
He could have kept on going on one engine, if only slow-and-steady. Once he had reached a safe altitude and stabilized the situation, he could have returned, with support from ATC, etc. Perhaps he was afraid of the second engine going out as well. This is what makes it so tragic.
BTW, Ross Ivey has a very interesting post on the updated article (2/20) about securing the emergency landing gear extension handle and how not doing so (not in POH instructions, despite it causing similar accidents) could lead to an engine going out.