Aviation Law Monitor : Aviation Lawyer & Attorney : Michael Danko Law Firm : California Airplane & Helicopter Crashes : Aviation Law Monitor

The NTSB released its preliminary report on the Pine Mountain Lake crash.  As usual, the preliminary report contains no conclusions concerning the cause of the crash. For that, we'll have to wait up to 4 years.  The preliminary report does, however, hint that the NTSB's investigation will focus on whether the pilot pressed on into weather beyond what the regulations allowed.

The full text of the report is here.  Some excerpts:

Instrument night meteorological conditions prevailed at the accident site, and no flight plan had been filed.

Instrument weather conditions are those that require a pilot to fly by reference to his instruments rather than by looking out the window. To fly in instrument conditions, a pilot must be instrument-rated, his plane must be properly equipped, and he must have a clearance from air traffic control.  He is not necessarily required to file a flight plan.  For example, instead of filing a flight plan, the pilot may have departed San Carlos in good weather and then obtained a "pop-up" clearance from air traffic control before entering instrument conditions at Pine Mountain Lake.  Nothing unusual or unsafe about that. 

A pilot, who stated that he flies to the airport most weekends, reported attempting to land a Cessna 510 while on an instrument flight plan, about 1 hour prior to the accident. He reported that throughout the instrument approach he was unable to identify the runway environment. He performed a missed approach, and diverted to Modesto where he landed uneventfully. He stated that he has flown into the airport utilizing the instrument approach regularly over the last few years, and this was the first time he had to divert to an alternate airport.

As discussed in this post, crash, a pilot on an instrument approach to runway 27 must "go missed" if he descends in the clouds to the minimum allowable altitude  -- in this case 770 feet above the ground --  and still can't see the runway.  Instead of going missed as required, some pilots will descend "just a little further" believing that, in just a few more seconds, they will break out of the clouds and the runway will appear before them.  Descending below the minimum altitude set forth in the instrument approach procedure is a violation of FAA regulations and a leading cause of instrument approach-related accidents. The NTSB seems to suggest that the pilot of the accident aircraft, N4175A, must have ventured below minimums to get beneath the clouds because the Cessna jet had to go missed.  However, the fact that the Cessna was forced to execute a missed approach at the airport one hour before the accident means little. Weather can change in an hour. 

The remaining two propeller blades were attached at the hub. All of the blades exhibited leading edge gouges, and varying degrees of tip twist. 

Gouges and blade twist is an indication that, the time of impact, the engine was developing power. Engine trouble can likely be ruled out.

A third witness, located 1/2 mile northeast of the approach end of runway 27, heard a low flying airplane, which he presumed was flying directly over his house, with engines running "full bore."

What was the pilot doing 1/2 mile northeast from the runway? (See image below.) As discussed in this post, the pilot should have been lined up for a straight-in approach.  And during the approach procedure, the pilot should have been throttled back for descent.  A pilot typically applies full throttle only when going missed.

Related Post: Piper Saratoga Crash at Pine Mountain Lake   

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The runway at Pine Mountain Lake is oriented east-west, and is surrounded by rugged terrain.  In poor weather, pilots are permitted to execute instrument approaches to the airport.  The approach procedures guide pilots as they descend through the clouds to the runway.  The procedures, flown properly, will place the pilot in a position to land straight ahead without having to maneuver.  When the pilot pops out of the clouds after flying the instrument approach to Pine Mountain Lake, his view out of the windshield should be something like this:  

The procedure the pilot must follow when approaching from the east is set forth below.  A pilot may descend in the clouds no lower than 770 feet above the runway.  To descend further, the pilot must be clear of the clouds and have the runway in sight.  If he cannot see the runway, he must "go missed."  That means he must abort the landing, and climb straight ahead by reference to his instruments until reaching a safe altitude.

Once the pilot has reached a safe altitude and has established radio contact with air traffic control, the pilot may attempt the approach procedure again.  He may obtain a clearance to fly a different approach procedure from the opposite direction, or he may opt to fly to a different airport where the weather is better.  

Investigators report that the accident aircraft, N4175A, "went missed" on his first approach to the airport, and that the accident occurred near the completion of its second approach.  On the second approach, the aircraft had successfully descended beneath the clouds.  We know that because

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The initial investigation was conducted by local law enforcement in conjunction with the FAA. Now the National Transportation Safety Board will take over.

The NTSB’s job will be to examine the wreckage and attempt to determine if the crash was caused by a defective aircraft part, negligent maintenance, or pilot error. The NTSB concedes, however, that it lacks the manpower, the technical expertise, and the funding to do that job properly on its own. Therefore, as a matter of long-standing policy, it will seek engineering assistance from the companies that manufactured the aircraft components in question. In this case, the NTSB will recruit the help of Cessna Aircraft, which manufactured the aircraft involved in the accident, Cessna N5225J, and Teledyne Continental Motors, which manufactured each of the aircraft’s two 260 horsepower engines. The NTSB will exclude members of the victims’ families and their technical representatives from the investigation, feeling that they have nothing to offer. (Sad but true.)

Of course, the NTSB’s practice of asking the manufacturers for help – a practice it calls “the party system” -- presents a conflict of interest.  After all, the manufacturers themselves might be the ones responsible for the accident. Some say that the NTSB’s party system is akin to asking the suspects for help in solving a crime. Nonetheless, the conflict – discussed further here – is ingrained in all NTSB investigations.

It’s no surprise that most NTSB final reports often favor the manufacturers who have “assisted” the NTSB investigators in their work. But perhaps it doesn't make any difference because, by federal regulation, the NTSB’s probable cause findings are not binding on anyone. The families are free to conduct their own investigation, and in the event of a lawsuit, the NTSB’s conclusions are given no deference whatever. In fact, in the event of litigation, the NTSB conclusions are not even admissible. Aviation attorneys who conduct their own independent investigations find that the NTSB’s conclusions are wrong about 50% of the time.

In one recent example, a Teledyne Continental engine similar to those installed on N5225J quit

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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.  With its landing gear 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 Tesla 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)

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A tail rotor system malfunction may have caused the crash of the EC135 helicopter that killed five on board the Food Service of America EC135 helicopter at Cave Creek, Arizona.  At least, that's where the current information seems to point.

Here are the key bits from an MSNBC report:

Witnesses saw parts flying off the stricken aircraft just before it crashed. Parts of the helicopter's rotors were found more than a half-mile from the main wreckage. . . witnesses reported hearing a popping sound, then seeing the helicopter rotate at least three times before the nose pointed down and it crashed.

The rotor parts that were found must have been tail rotor parts.  The helicopter could not have continued in flight for another half mile if it had lost any part from one of its main rotor. Instead, it would have crashed immediately.

The main rotors keep the helicopter in the air. The tail rotors keep it from spinning in a direction opposite to the rotation of the main rotors. Reports that the helicopter rotated are therefore consistent with a malfunction of the tail rotor or the tail rotor drive system.

The weight of the helicopter is balanced under the main rotor mast.  The fact that the helicopter suddenly pointed down indicates that a heavy part, such as a tail rotor transmission, fell off the tail, thereby rendering the helicopter too "nose-heavy" to remain in the air.

Investigators will be looking closely at the helicopter's maintenance history. In 2007, another EC 135 crashed in Japan.  That crash was attributed to a failure of a tail rotor drive component.  As a result, the FAA issued an emergency airworthiness directive (reproduced below), requiring that all EC135's be inspected and that parts be replaced as necessary to prevent similar tail rotor failures and loss of control.  

This Emergency Airworthiness Directive (EAD) is prompted by a report of a fatal accident involving the failure of a tail rotor control rod (control rod). This condition, if not corrected, could result in the failure of a control rod and subsequent loss of control of the helicopter.  

AD2007-26-51

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Updated February 12:

A Cirrus SR-20 single engine aircraft collided with a Pawnee tow plane that was pulling a glider. The Cirrus reportedly ran into the Pawnee's tow line. The Pawnee crashed and the pilot was killed.  The occupants of the Cirrus were also killed.  The glider pilot, however, recognized the impending collision, released his aircraft from the tow line, and landed without injury to himself or his two passengers.

Each Cirrus aircraft is equipped with a rocket-propelled parachute.  One purpose of the parachute is to safely return the aircraft to earth if it is damaged in a mid-air collision.  Unfortunately, the parachute didn't help in this case. Video of the Cirrus wreckage, on fire, descending beneath its canopy is here.

Some questions:

Who had the right of way?

Gliders and tow planes have the right of way over other aircraft.

Why couldn’t the Cirrus pilot see and avoid the Pawnee's tow line?

The tow lines are nearly invisible in the air. But despite the news reports, the Cirrus most likely collided with the Pawnee tow plane itself, not with the tow line.  [The glider pilot has now confirmed to the NTSB that the Cirrus collided with the Pawnee’s fuselage, not the towline.] That explains the tremendous damage to the Cirrus and the Pawnee, and the immediate fireball that resulted, as reported by the glider pilot.

Doesn’t the Cirrus have radar to help avoid other aircraft?

No radar, but some Cirrus aircraft are equipped with other devices to detect and help avoid other traffic.  That equipment is optional, however, and may not have been installed in this particular Cirrus. [Reports are that the Cirrus was not so equipped when it left the factory.]  Even if it was installed, it only detects aircraft that have an operating transponder. Most gliders don’t have transponders. We don’t know whether the Pawnee’s transponder was on.

What good is the Cirrus parachute if the aircraft burns after a mid-air collision?

Some argue that the Cirrus is not crashworthy because it is prone to post-impact fires.  That's because it is made largely of fiberglass rather than aluminum.

It is true that aircraft should be designed so as not to burn after an accident.  However, that standard applies only when the crash is otherwise survivable. The impact forces in this accident appear to have been so great that the accident was not survivable. That makes it hard to blame the design of the aircraft for the post impact fire.  In fact, the occupants were likely killed on impact, making the fire irrelevant to the tragic outcome. (The parachute was likely deployed as a result of impact forces acting on the parachute's igniter cable, not by the aircraft's occupants.)   

Was this a freak accident?

Maybe, maybe not. Here is a video of a remarkably similar accident. The camera plane hit a tow plane's cable, rather than the tow plane itself.  The camera plane was equipped with a parachute, like the Cirrus was in this case.  The pilot deployed the parachute and ultimately walked away from the crash. 
 

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Icing or pilot error?

Last April, the NTSB released the data from Flight 3407's FDR.  I blogged about that here.  Despite wide spread speculation that icing brought down the aircraft, it looked to me like pilot error -- not weather --  was to blame. 

Then, in May, the NTSB released an animation derived from the aircraft's flight data recorder, its cockpit voice recorder, and ATC transcripts.  I blogged about that here.  The animation, like the raw data from the FDR, made a strong case for pilot error.  From the animation, it appeared to me that an inattentive pilot allowed the aircraft to get slower and slower, until it became dangerously close to the speed at which the aircraft would stop flying altogether and simply fall from the sky.  Then, when the critical moment came, the pilot pulled back on the control yoke instead of pushing it forward, thereby inducing an aerodynamic stall.

The NTSB made public its official probable cause finding at a hearing yesterday.  No surprises to anyone who has studied the data.  According to an article in today's Buffalo News, the NTSB summed it up as follows: 

The plane got so slow that the "stick shaker" — a device that helps to prevent stalls — activated. But Renslow [the pilot] mistakenly pulled back on the plane's controls at that point, which is exactly the opposite of what he should have done.

In total, Renslow pulled back on the controls three times in response to the stick shaker and "stick pusher," forcing the nose upward. That caused and then exacerbated the stall.

It's almost unimaginable that a professional pilot would make the series of mistakes that the pilot did in this case.  Even a new student pilot would know better.  But that's what he did.

The NTSB played its animation for those who attended the hearing.  The animation shows the pilot's errors mount.  The activation of the "stick shaker" is depicted 2 minutes and 8 seconds into the animation. The shaking control yoke was a final warning to the pilot that he must immediately push the yoke forward.  But instead of pushing forward, the pilot pulled back. Three times.  After the third time, the aircraft stalled and crashed. 

There were countless points at which this aircraft could have been saved but, inexplicably, the pilot failed to take appropriate action.  

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The NTSB's preliminary report on the crash contains little more than what was in the news accounts. The report does, however, offer one bit of new information.  The helicopter impacted on a magnetic heading of 230 degrees.  That heading is not in line with the route from Reno to Susanville.  While that might ultimately prove to be important, little can be made of that information without a careful examination of the layout of the terrain near the accident site and the roadway that the pilot might have been using to aid in his navigation.     

Though the information in the NTSB's official report is sparse, an NTSB spokesman did offer his expanded comments to Mary Pat Flaherty, a reporter for the Washington Post who has been following the poor EMS safety record during the past months. The NTSB's Ted Lopatkiewicz told Flaherty that the Mountain Lifeflight helicopter didn't have certain important safety equipment.  Lopatkiewicz was referring to the helicopter's lack of an autopilot, a ground proximity warning system, night vision goggles (discussed in this post), and other equipment necessary to navigate in poor weather.

But in this case the pilot was flying in good weather.  He did not collide with the ground because he could not see it.  Rather, as discussed here, it appears that the pilot crashed because of some type of mechanical problem with the helicopter.  It's unlikely the helicopter's lack of advanced equipment played any role in the accident at all. 

Related Posts:

Compensating the Families of the Mountain Lifeflight EMS Crash

Mountain Lifeflight EMS Helicopter Crash at Doyle, California

EMS Helicopter Safety: NTSB Pushes the Envelope

OSC: FAA Ignoring EMS Helicopter Dangers For Fear of Negative Publicity 

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At its annual convention in San Francisco, the California Trial Lawyers Association, known as the Consumer Attorneys of California, honored aviation accident attorney Mike Danko as a Trial Lawyer of the Year finalist for 2009 in recognition of our work in Burdett v. Teledyne Continental Motors. The Trial Lawyers Association showed this video presentation during the ceremony.

The case involved the forced landing of a Beech Bonanza after theTeledyne Continental IO-550 engine installed in the aircraft came apart in cruise flight.

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An A-Star AS350B air ambulance helicopter crashed November 14 at Doyle, California, killing the three crew members on board.  According to an article in the Reno Gazette Journal, the pilot made a distress call before the crash. That indicates that the pilot was likely experiencing a mechanical emergency. The photographs accompanying the article show that the wreckage was spread over a fairly large area.  That indicates that the pilot lost control of the helicopter well before he was able to attempt an emergency landing.

Under the circumstances, the NTSB will be looking at the helicopter's hydraulic actuator system carefully.  The actuators move the helicopter's rotor blades, allowing the pilot to control the flight of the aircraft. The AS350B's hydraulics -- similar to a power steering system in a car --  help move the helicopter's actuators. 

The A-Star helicopter's hydraulics have a troubled history. The hydraulic system seems to fail frequently.  Without hydraulic assistence, the pilot may find it hard to move the actuators and thus the helicopter can be difficult to control.  In fact, one of the country's largest operators of A-Star helicopters is on record as saying that the design of the helicopter's hydraulic system is so prone to failure that it is defective and dangerous and needs to be redesigned.  

While a problem with the hydraulic system can make the helicopter difficult to control, a disconnected actuator control rod will make the helicopter impossible to control. That's what happened in 2007, when an AS350B just like the one in involved in this accident crashed in Hawaii, killing four tourists.

Days after the accident in Hawaii,  the A-Star helicopter's manufacturer, Eurocopter, issued a Special Airworthiness Bulletin (see below) prompted by two previous fatal accidents, warning of the consequences of loose servo control rod end fittings. 

This condition could lead to flight control disconnect and subsequent loss of aircraft control. Two fatal accidents have occurred after the servo-control rod end-fitting became detached from the servo-actuator. 

Of course, it's far too early to say what caused the Mountain Lifeflight accident.  But the helicopter's hydraulic actuator system is certainly something that needs to be looked at very carefully.

December 6 Update: More on this accident here.

January 14 Update: On Compensating the Mountain Lifeflight Families here. 

AS350BService Bulletin

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I blogged about Scene Systems' animation of Flight 1549's landing in the Hudson here back in March.  Great effort, but I noted that it would take hundreds more hours of work before it could be used in court.  That's because it did not appear that the animation accounted for and synchronized all the available data for the flight.  For example, the flight path depicted in the animation could not have been true to the information from the flight data recorder, because the flight data recorder had not yet been downloaded and made available by the NTSB.  As a result, Scene System's finished product involved too much guesswork to ever be shown to a jury.

Just for fun, Kas Osterbuhr of Exosphere3d in Denver has been working on perfecting an animation ever since.  He emailed me the link late last night.  Kas, whose firm creates animations for use in court, explained to me that his animation is pretty much technically perfect.

Among the datasets utilized are: audio transcripts and recordings, digital flight data recorder, raw radar data, NEXRAD weather, witness statements, satellite imagery, elevation maps and several of the NTSB reports published in the docket. . .All aspects of this animation are based on actual data, whether from the NTSB docket or otherwise. The entire 3D reconstruction is built into a single environment where every piece of information can be aligned in position and on a timeline.

Tons of work went into this animation and it shows.  Aviation accident animations don't get any better than this.

One question, Kas.  The animation depicts flames coming from the aircraft's engines at certain times.  On what data is this based and what would happen if the judge ultimately determined that that evidence for this aspect of the animation is insufficient to allow it to be shown to a jury?  

November 9 Update: Kas' response is in the comments.

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The families of Michael and Anne Harris, the American couple on board Air France Flight 447, filed suit this week in Houston federal court.  It's the first lawsuit arising from the crash. The most frequently asked questions about this suit are:

Question:  Aren't the families jumping the gun?  The black boxes haven't yet been recovered, and may never be.  For all we know, this may have been the result of a chance encounter with a thunderstorm.  The crash may have been an unavoidable accident with no one to blame.

Answer: The Montreal Convention is the international treaty that governs all claims against airlines involving international air travel.  Under the convention, Air France is responsible even if the the crash was "just an accident."  As a result, Air France must compensate the families for their loss regardless of what the cause of the crash turns out to be.

Question: Flight 447 was from Rio de Janeiro to Paris on a French airline.  Why should the families be allowed to sue in Houston, of all places?

Answer: The Montreal Convention allows the families to sue in the country of the passenger's "principal and permanent" residence.  The families say that, though the couple was living in Brazil, the couple maintained a permanent residence in The Woodlands, a suburb of Houston.  If that's so, the families are entitled to sue in Houston.

Question: Why did the families file suit in federal court, rather than state court?

Answer: Many aviation lawyers believe that state courts are more favorable than federal courts for family members who have suffered a loss.  So victims' attorneys often prefer to sue in state court.  However, a fairly new federal statute requires almost all cases arising from large air disasters to be heard in federal court.

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NTSB Chairman Deborah Hersman's recent testimony before congress concerning the mid-air collision over the Hudson raises more questions than it answers.  She stated that  the Teterboro controller instructed the Piper pilot to switch to frequency 127.85 to contact the Newark controller.  But before leaving the Teterboro frequency, according to Hersman, the pilot read back to the controller "127.87,"  which was wrong.  Thereafter, the pilot was in contact with neither Teterboro nor Newark, and so neither facility could warn him of the impending collision. Hersman's remarks are here.

Hersman's implication is that the Teterboro controller failed to correct the pilot, and so the controller contributed to the pilot's getting "lost in the hertz" (out of radio contact) at a crucial moment.  However, the animation that the NTSB released on the same day that Hersman testified does not appear to back Hersman up.  It just doesn't sound as though the pilot read back "127.87" as Hersman states.  You can listen to the audio yourself beginning at minute 2:25. 

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We count on the NTSB to get the facts right. That confidence is, unfortunately, sometimes misplaced. The truth is that the NTSB gets it wrong. A lot. I’ve written about that here, here, and here.

The NTSB has now given us further reason to question whether it deserves the confidence we place in it. On Friday, the NTSB came out with a block-buster press release condemning the Teterboro air traffic controller who had cleared the Piper airplane for takeoff. According to the NTSB's report, the Teterboro controller could see on his radar screen that the Piper pilot was on a possible collision course with the Liberty Tours helicopter. In fact, according to the NTSB, the controller could see the conflict before the Piper pilot switched off from the Teterboro controller’s frequency. Yet, according to the NTSB, the controller failed to warn the Piper pilot.

At 1152:20 the Teterboro controller instructed the pilot to contact Newark on a frequency of 127.85. . . At that time there were several aircraft detected by radar in the area immediately ahead of the airplane, including the accident helicopter, all of which were potential traffic conflicts for the airplane. The Teterboro tower controller, who was engaged in a phone call at the time, did not advise the pilot of the potential traffic conflicts.

That was wrong. True, the controller was on the phone when he should not have been.  But the helicopter did not appear on the controller’s radar screen until after the Piper pilot was supposed to have switched to a new frequency. Of course, by then it was too late for the controller to advise the pilot of anything. In other words, it appears that there was nothing the controller could have done -- whether he was on the phone or not.

Over the weekend, the air traffic controllers’ union privately asked the NTSB to correct its error. The NTSB refused. So today the union issued its own press release setting the record straight.  The press release claims that the NTSB's account, which implies that the controller should have prevented the accident, is "outright false" and "misleading."  Worse, it charges that the NTSB knows it, but refuses to correct its error.

This afternoon, after the controllers' union went to the press, the NTSB finally conceded that it was, in fact, wrong. It thus issued a new press release, explaining that the controller could not have seen the helicopter after all.

The accident helicopter was not visible on the Teterboro controller's radar scope at 1152:20 [when the controller instructed the Piper to change frequencies]; it did appear on radar 7 seconds later - at approximately 400 feet.

The NTSB offered no apology for its error. Nor did it offer an explanation. Rather, despite that the union was right, and the NTSB was wrong, the NTSB’s only reaction was to kick the union off the investigation.

The NTSB’s blunder was a whopper. It laid blame for the accident where it does not appear to belong.  The NTSB's only interest is supposed to be in getting the facts right. If that’s so, why did it not correct its error when the union asked it to?  Why did it require the union to force the issue? 

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Compared to pilots in other countries, pilots in the US have extraordinary freedom. Of course, to keep commercial airliners safe from collisions, pilots of small aircraft are excluded from certain airspace near major airports unless they have first obtained a clearance from air traffic controllers.  If a pilot obtains the necessary clearance, controllers will dictate the pilot's path and use radar to monitor the pilot's every move. 

But that still leaves many places where pilots are permitted to fly without being supervised or controlled in any way.  One such area, appropriately enough, is near the Statue of Liberty.  As long as the pilot stays below 1100 feet -- outside the airspace used by airliners -- the pilot doesn't need a clearance, doesn't need to have filed a flight plan, and doesn't need to communicate with any tower or other air traffic control facility. The pilot is totally on his own.

Many non-pilots are surprised to learn that the method used to prevent collisions in such uncontrolled areas is called "see and avoid."  The pilot is supposed to look out his window, "see" the other aircraft, and "avoid" them.  Pilots talk about having to "keep their head on a swivel" when flying in uncontrolled airspace. Though this method of collision avoidance may sound primitive, over the years it has worked well.

There is one problem.  Helicopters and airplanes don't mix well in a "see and avoid" environment.  Helicopters fly slower than airplanes.  And because they have a small cross section, they are hard to spot -- especially when viewed from directly behind. That puts them at risk of being rear-ended.  It doesn't help matters that helicopters tend to manuever in a fashion that most airplane pilots find to be unpredictable. 

Because of all that, helicopter pilots are supposed to "avoid the flow" of airplane traffic.  In other words, as best they can, they are supposed to stay out of the way. Unfortunately, when both a helicopter and airplane are headed to the same spot, or are both looking at the same feature on the ground, that can be difficult to do.

We don't know what factors combined to result in the midair over the Hudson.  But the NTSB has long recognized that when it comes to uncontrolled airspace, helicopters -- especially tour helicopters -- don't mix well with airplanes.

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The G36 Bonanza's closest competitor is probably the Cirrus SR22. Would the outcome of this accident have been different had the Beechcraft been equipped with a ballistic parachute system, like the system installed in the Cirrus, depicted here?  Probably not.  For the Cirrus' ballistic parachute to work, the plane needs at least 400 feet of altitude.  Although we don't know how high N618MW climbed before its engine quit, it's unlikely it reached 400 feet.  That's an altitude the aircraft probably wouldn't have achieved until well after crossing the end of the runway. As this illustration shows, the Bonanza never made it that far.

The NTSB has now released its Preliminary Report.  The report can be found here.  There's no new information in the report, and certainly nothing that causes us to rethink the analysis we wrote about here.  

As usual, the NTSB report contains no conclusion concerning the cause of the crash.  For that, we have to wait until the NTSB issues its Probable Cause report.  Some news sources, such as the one here, are reporting that the probable cause report will be issued in the next 6 to 9 months.  That's doubtful. Except in the simplest of cases, it takes the NTSB at least 18 months to issue its probable cause report.  Sometimes, it can take as long as four years.    

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Bonanza N618MW, a Beechcraft like the one pictured below, was doing "touch & goes" at Jack Northrop field in Hawthorne.  "Touch and goes" are practice landings where the pilot does not stop on the runway.  Instead, after the wheels touch down, the pilot advances the throttle, takes off again, and then circles around for another landing.  Everything appeared to be fine until, on one of the "goes", the Bonanza's engine quit.  The Bonanza crashed into a parking lot.  The three people on board were killed. 

Why did the engine quit?

Fuel?  Most engine failures are the result of either fuel exhaustion (no avgas in any of the aircraft's tanks), fuel starvation (pilot fails to switch to a full tank when the one he is using runs dry), or fuel contamination (water or jet fuel has found its way into the avgas).  So in any case involving engine failure, fuel has to be considered.

When, as here, there is no post-crash fire, fuel exhaustion is a prime suspect. No fire often means that there was no avgas (aviation gasoline) on board to burn. But it's unlikely this accident was caused by fuel exhaustion.  Though it didn't ignite, there was plenty of avgas spilled on the parking lot where the aircraft crashed. That means there was fuel on board.

Did the pilot fail to switch to a full tank when the one he was using ran dry? That, too, is unlikely.  Witnesses reported that the aircraft was streaming smoke.  An airplane doesn't stream smoke when it runs out of gas.  So both fuel exhaustion and fuel starvation can probably be ruled out as a cause of the engine failure..

Could the engine have quit because of fuel contamination?  If the avgas was contaminated with either water or jet fuel, the engine would have failed on the first takeoff. It would not have been able to perform multiple takeoffs before quitting. Nor would the engine have smoked. We can likely rule out fuel contamination.

Mechanical Failure.  Once fuel issues are ruled out, mechanical failure appears as the next most likely cause of the engine's quitting. Aircraft engines are not supposed to fail without warning. When they do, it is often because of something the engine manufacturer did or failed to do. For example, the manufacturer may have designed the engine improperly or carelessly assembled it. Some of the legal theories that the victims' families can assert to hold the manufacturer responsible are discussed here and here.

The engine installed in N618MW was a model IO-550.  It was manufactured by Teledyne Continental Motors.  Engine manufacturers such as Teledyne often try to avoid liability for causing an accident by asserting the protection of the General Aviation Revitalization Act, or GARA, discussed here.  However, the engine installed in N618MW was manufactured in 2005.  GARA does not apply to engines that are less than 18 years old, such as this one, and so the families will be legally permitted to hold Teledyne responsible for any defects in the engine.

The NTSB Investigation.  The NTSB is investigating the cause of the crash.  The NTSB will ask Teledyne Continental Motors to participate in the investigation, and to help it determine the cause of the accident.  As part of the investigation, the NTSB, along with representatives of Teledyne, will disassemble the engine and test its various parts. (Pictured right is an IO-550 engine being disassembled after a crash in 2001.) Of course, since Teledyne itself might be responsible for the crash, it's participation in the investigation presents a conflict of interest.   It is like the police asking the suspect for help in solving the crime. To make matters worse, the NTSB will not allow the victims' families or the families' lawyers to participate in the investigation at all. The conflict of interest is discussed further here.

The conflict of interest makes for biased NTSB reports that tend to favor the manufacturers.  In one recent case, a Teledyne model IO-550 engine -- just like the one in this case -- was installed in a Beechcraft Bonanza that had departed Van Nuys, Californa.  The engine quit and the plane crashed. The NTSB asked Teledyne Continental Motors to participate in its investigation and help it determine why the engine failed.  Not surprising, after hearing only Teledyne's side of the story, the NTSB determined that the engine failed because of poor maintenance, and not anything that Teledyne did.  In fact, the NTSB cleared Teledyne completely of any blame.  We investigated ourselves and later brought the matter to trial. After hearing all the evidence in the case -- not just the evidence favorable to Teledyne -- the jury disagreed with the NTSB.   The jury determined that the engine quit because Teledyne's IO-550 maintenance manuals were wrong, and awarded the injured passenger $15 million. 

What to do? Teledyne Continental Motors and its lawyers are already "investigating" the crash.  The families should consider retaining competent aviation lawyers immediately.  The families' lawyer can begin their own investigation and make sure that important evidence is preserved.  Unfortunately, the families cannot rely on the NTSB to find answers. They need to find their own.

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Two months ago, Scene Systems -- a litigation support firm -- released its animation of Flight 1549's crash into the Hudson. I posted here that, in all likelihood, the animation would not be admissible in court. The legal objection would be that the animation "lacked foundation." For example, without information from the Airbus' black boxes, Scene Systems couldn't confirm the aircraft's flight path or guarantee that the Air Traffic Control audio was properly synchronized to the aircraft's path of travel.  Therefore, the animation involved too much guesswork to be shown to a jury.

The National Transportation Safety Board has now released its own animation. Having retrieved the black bloxes, the NTSB was able to plot accurately the Airbus' position, speed, and altitude at each point along the aircraft's short flight.  The NTSB then properly synchronized the Air Traffic Control audio to the aircraft's flight path.

The only audio on the NTSB's animation is the radio transmissions between the crew and Air Traffic Control. As is typical, the NTSB did not make public the audio of the cockpit conversation between the captain and the first officer. The NTSB did, however, prepare a written transcript of that conversation. The NTSB superimposed the transcript on the animation. (HOT-1 is the pilot, HOT-2 is the first officer.)

Would this animation be admissible in court?  While Scene System's animation would not pass legal muster, the NTSB's work probably would. 

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The pilot's original destination was Bozeman, Montana.  But the pilot amended his flight plan and diverted to Butte.  The pilot did not tell air traffic control why he was diverting.  About 25 minutes later, as the aircraft approached for landing at Butte, it went out of control and crashed. 

The NTSB is now investigating two things: (1) why the pilot diverted to Butte, especially when he was so close to Bozeman, and (2) why the pilot lost control and crashed so near the runway at Butte.

Some possible explanations for diverting include:

• Low fuel;
• Concerns about weather at the destination;
• Sick passenger;
• Need for a bathroom;
• Mechanical issues;
• Medical issue afflicting the pilot.

Some possible explanations for losing control of an aircraft on approach to landing include:

• Mechanical/structural issues;
• Icing;
• Improper weight and balance (aircraft load not properly distributed);
• Pilot error;
• Medical issue afflicting the pilot.

 “Occam’s Razor” suggests that a theory relying on one anomaly to explain an accident sequence is more likely to be correct than one relying on two anomalies. In other words, the simplest answer is usually the best answer.  Here, one anomaly that explains both the mysterious diversion to Butte and the loss of control 25 minutes later is a medical issue afflicting the pilot.

A Butte coroner, Lee LaBreche, autopsied the pilot. He found that the 65 year-old did, in fact, have heart disease.  He thus noted that "the presence of a pathologic condition of the heart causing this accident cannot be excluded."  Nonetheless, LaBreche felt a heart attack was unlikely because the pilot never reported any symptoms to air traffic control. According to Examiner.com:

Federal investigators have said that in [the pilot's] last recorded communications with air traffic controllers he gave no indication of any problems. LaBreche said that supports the premise that there was no medical emergency.

The coroner's reasoning is flawed. Pilots have little hesitancy about reporting mechanical problems.  However, a pilot would be very reluctant to report to air traffic control that he is having the symptoms of a heart attack.  That sort of report will keep a pilot grounded for a long, long time, even if the symptoms ended up being a false alarm. So, while the fact that the pilot reported no problems may support the premise that he had no mechanical issue, it says nothing about whether he had a medical issue.  For those who favor Occam’s Razor as an investigatory tool, a heart attack is the most likely cause of this accident.

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Tim Vasquez is a meteorologist with Weather Graphics in Oklahomoa.  He has plotted Flight 447's flight path against GOES-10 satellite and other weather data. Vaquez' work suggests Flight 447 penetrated two thunderstorm cells.

The image below, according to Vasquez, is similar to what the Flight 447 crew would have seen on its weather radar screen, assuming its radar was working. The black line in the image represents the aircraft's flight path.  "ACARS Position" represents the aircraft's position when it sent it's last ACARS message.

This next diagram is a cross section of Flight 447's track through the thunderstorm cluster.  According to Vasquez, instead of fying around these two cells, Flight 447 flew through the top of the first cell and then continued on through the middle of the second.

Not surprisingly, Vasquez concludes the aircraft encountered severe turbulence that may have damaged the aircraft.  The question of why Flight 447 failed to avoid the storms (theories discussed in a previous post) remains unanswered.  Vasquez's full report can be found here.

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Did the Pilots Attempt to Fly Through a Thunderstorm Intentionally? That's very unlikely. Pilots avoid thunderstorms at all costs, because they know a thunderstorm can destroy any aircraft. Pilots use the aircraft’s on-board weather radar system to make sure they keep a safe distance. During the day, they can see the towering thunderstorms rising up to 50,000 feet and avoid them that way as well.

Did Lightning Destroy the Aircraft? Probably not. Lightning strikes are common. On average, each airplane is the US commercial fleet is stuck by lightning once per year. To protect against strikes, airliners are designed to route the electrical charge along the aircraft’s outer skin from one end of the aircraft, where the charge usually originates, to the other, where it leaves the aircraft harmlessly. Because the aluminum aircraft skin is a good conductor, it is fairly easy for engineers to make sure the path from one end of the aircraft to the other is unbroken, thus assuring that the aircraft will not be harmed.

The Airbus makes extensive use of composite (non-metallic) materials. This makes lightning protection more of an engineering challenge. Engineers have to take extra steps to make sure the conductive path is unbroken by, for example, embedding the composite parts with metallic mesh.  The mesh maintains a conductive path along the aircraft's exterior.

If there is a discontinuity in the conductive path, the lightning can cause a “burn-through” of the aircraft structure, which can be catastrophic. In addition, sparks can ignite fuel tanks. However, the last time an aircraft was brought down by a lightning strike was 40 years ago. So while lightning can theoretically cause catastrophic structural damage, it is unlikely.

Did Lightning Have Anything at all to do With the Loss of the Aircraft?  It is possible that non-structural damage from a lightning strike could have contributed to the loss of the aircraft.
 

Weather Radar Antenna. A lightning strike could easily have damaged the aircraft’s weather radar antenna, located in the aircraft’s nosecone. Manufacturers contend that the antenna cannot be completely protected from lightning if it is to function properly. If the antenna is struck by lightning, it could render the radar inoperative. In the dark of night, this could make it difficult for the pilots to avoid flying into a thunderstorm, resulting in the loss of the aircraft.

Electrical System. The Airbus’ "fly-by-wire" flight controls are heavily dependent on the aircraft's electrical system. A lightning strike can disrupt the aircraft electronics. Without assistance from the aircraft’s electrical system, an Airbus can be difficult to control – sort of like trying to drive a car without the power steering. While Airbus pilots are prepared to fly without a fully functioning electrical system, in areas of severe or extreme turbulence, it may be impossible to keep the aircraft upright.  Losing control of the aircraft for even a short time can overstress the structure and cause the aircraft to break apart.

Does the Fact that there was No Distress Call Mean Whatever Happened Was Sudden? No. When faced with an emergency, pilots are on their own. There is nothing someone sitting in a cushy chair 1000 miles away can do to help. Communicating his predicament is far down the list of a pilot's priorities, except in TV movies.

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I blogged here on whether it was icing that caused the crash of Flight 3407, or whether the pilot simply pulled back on the yoke when he should have pushed forward.  The NTSB's animation, using data gathered from the aircraft's black boxes, makes a strong case for the latter. 

The video is 2 minutes 39 seconds long.  Watch the airspeed drop dangerously low by 2:04 and the stick shaker activate at 2:07.  The pilot should have immediately pushed the yoke forward, which would have pointed the nose down and allowed the aircraft to regain airspeed.  Instead, he pulls the yoke back.

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Corey Lidle's wife and Tyler Stanger's family are suing Cirrus Design, alleging that a problem with the plane's flight controls caused Lidle and Stanger's plane to crash into a Manhattan hi-rise.

Miles O'Brien, a former CNN correspondent, calls the lawsuit frivolous, because the NTSB concluded the cause was pilot error.  According to O'Brien, "in our litigious society, the facts don't matter for much."

O'Brien is missing the fact that the NTSB's conclusion is marred by a built-in conflict of interest. That’s because the NTSB allowed Cirrus to participate in the investigation, but not the families or the families’ experts. Is it any surprise that the NTSB’s final conclusions favored the manufacturer?

There is a known problem with the Cirrus ailerons jamming at full deflection. After this accident, Cirrus published a number of service bulletins in an attempt to correct the problem and, ultimately, the FAA issued an Airworthiness Directive against the aircraft. That doesn't necessarily mean that the aileron problem caused the Lidle crash. But the families are entitled to use the power of subpoena that comes with filing a lawsuit to investigate what happened. They don’t have to simply accept the NTSB’s conclusion — a conclusion the NTSB reached after closed-door meetings with Cirrus’ experts. 

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Right after the crash of Flight 3407 at Buffalo, investigators  focused on the aircraft's deicing system. The question, as explained by former CNN reporter and pilot Miles O'Brien, was whether ice had accumulated on the plane's wings faster than the de-icing system could remove it, leading to an aerodynamic “stall,” or loss of lift. 

But as the investigation progressed, it began to look as though, just before the pilot lost control of the aircraft, the nose of the plane pitched up  -- not down as usually happens when ice overwhelms an aircraft.  That raised an almost unthinkable possibility:  gross pilot error.  When an aircraft gets too slow and is about to stall (that is, quit flying), the pilot is supposed to push forward on the yoke and pitch the nose down, not pull back.  If the pilot pulls back, the nose will pitch up at exactly the wrong moment and the plane will stall. 

This is basic airmanship.  In fact, every student pilot is taught the proper stall recovery technique before he makes his first solo.  Could a professional airline captain have caused the crash by pulling back on the yoke instead of pushing forward?  Well, not only did the nose pitch up, but the aircraft's flight data recorder showed that the pilot did, in fact, pull back on the yoke just before losing control of the aircraft.

Now two prominent aviation law firms, representing different families, are taking different tacks. The first firm, the Clifford Law Firm in Chicago, has filed suit on behalf of two families, alleging that the aircraft crashed because it was inadequately equipped to deal with icing.

The second firm, Kreindler & Kreindler, representing 10 of the families of Flight 3407, says that pilot error caused the crash, not icing or any defect in the aircraft's deicing equipment.

Which is it? A defective de-icing system or pilot error? Commuter turboprops have a history of crashing due to ineffective de-icing systems, and they are most vulnerable when on approach to landing,  just as was Flight 3407. I represented the family of the pilot killed in the crash of Comair Commuter Flight 3272 near Monroe Michigan in 1997. All aboard were lost for just that reason – a defectively designed de-icing system that the FAA should never have certified.  And some of the similarities between Flight 3407 and Flight 3272 are striking. 

But, in this case, it is hard to square the information from the flight data recorder with anything other than pilot error.  Is it possible to come up with a scenario where pulling back on the yoke was anything but a very bad piloting mistake?  Yes.  Pulling back on the yoke, instead of pushing it forward, can be considered an appropriate reaction, for example, when ice overwhelms the tail of the aircraft rather than the wings.  But as explained by airline pilot and Salon columnist Patrick Smith, it is unlikely that the pilot was faced with tailplane icing.  That leaves pilot error as the most likely cause of the crash.

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Scene System's animation of the crash of US Airways Flight 1549 is a viral hit.  The litigation support firm combined available ATC audio tapes, flight track information, and an on-scene photograph into a great recreation.  This is the exactly the type of animation used in court to help juries understand the details of an aviation accident.  

But would this particular animation be admissible in a lawsuit?  Probably not. It incorporates too much guesswork.  For example, Scene System overlays the animation with audio from Air Traffic Control tapes.  Are the movements and positions of the aircraft properly synchronized with the audio? To do that right, you'd most likely need information from the Flight Data Recorder , which isn't yet available. Without that data, the animation is objectionable as "lacking foundation."  It's safe to say that, before it could be shown in court, the animation would require hundreds more hours of work and refinement. 

Of course, Scene Systems wasn't out to produce a recreation that was admissible in court. It was just trying to show the type of product it is capable of. And it did that very nicely. 

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