Accident Investigations

The Cessna T310Q crashed shortly after takeoff.  For clues into the cause of the crash, the press has focused on the fact that the pilot, Nouri Hijazi, had difficulty getting the engines started. 

But what one witness had to say suggests that the plane was improperly loaded – specifically, it had too much weight in the back. According to the San Jose Mercury News, the witness watched the plane head off to the runway and saw something odd: 

[The witness] said she watched uneasily as the plane slowly taxied for takeoff.  As it did, the plane rocked back and forth, front to back, its tail nearly touching the ground. 

That can happen when there is too much weight in the back of the plane. And when an aircraft is loaded such that is isn’t in proper balance, it can become uncontrollable shortly after takeoff and enter an aerodynamic spin or stall, even with the engines developing full power.  That is, though there engines are running fine, the aircraft will stop flying and simply fall out of the sky.  Judging from the security camera footage of the crash, something like may have happened. The video show the aircraft "falling" rather than "flying."  

Aviation expert Clive Irving suggests that, because the Egypt Air pilots made no mayday call, they must have been killed before the aircraft crashed.  In other words, the crash was the result of terrorism rather than a mechanical issue.

Normally in a fire and smoke emergency the pilots would have time to don smoke masks with microphones in them, and would be able to send a Mayday, and describe the problem. The Egyptian pilots clearly were never able to do this, suggesting the possibility that they were either disabled or killed at the onset of whatever overcame the airplane so rapidly.

I’m guessing Mr. Irving never experienced a significant in flight emergency.  Those who have understand that the last thing a pilot facing an emergency feels the need to do is broadcast a mayday or “describe the problem” to some air traffic controller sitting in a warm dark room hundreds of miles away, sipping coffee.  And calling air traffic control to “describe the problem” is a task that appears on few, if any, emergency checklists.   Sure, pilots in distress broadcast “Mayday! Mayday!” all the time – in the movies.  But that’s about it.

“Mayday” is from the French, “m’aidez”, meaning “help me.”  When you are 6 miles over the ocean and dealing with smoke in the cockpit there is nothing an air traffic controller can do to help you.  Nothing at all.  The smoke is entirely your problem.  In an emergency, communicating with an air traffic controller is most often a distraction to be avoided or at least deferred until time and bandwidth permits. 

We don’t yet know whether the flight 805 crashed due to a mechanical problem or a terrorist act.  But the fact that the pilots made no mayday call suggests nothing.

Today a Bell helicopter crashed into Pearl Harbor near the Arizona Memorial.   Reports are that everyone survived.  

 

 

Some are saying the helicopter experienced engine failure.  Unlikely.  Instead, the pilot probably experienced "settling with power."  That’s when the helicopter is forced down by the downdraft it   creates with its own rotors.  To avoid crashing, the pilot must ease up on the power.  In the video, you can hear power increasing.  Adding power (or torque) just makes things worse.   

Settling with PowerFrom the FAA’s Rotorcraft Flying Handbook:

When recovering from a settling with power condition, the tendency on the part of the pilot is to first try to stop the descent by increasing collective pitch. However, this only results in increasing the stalled area of the rotor, thus increasing the rate of descent. Since inboard portions of the blades are stalled, cyclic control is limited. Recovery is accomplished by increasing forward speed, and/or partially lowering collective pitch. In a fully developed vortex ring state, the only recovery may be to enter autorotation to break the vortex ring state. When cyclic authority is regained, you can then increase forward airspeed.

Piper N36402 departed Reid-Hillview Airport for Las Vegas as it was getting dark.  The pilot had his wife and three children on board.  Though the weather was challenging, the aircraft was turbocharged, which would have allowed the pilot to climb above at least some of the clouds.  

The plane’s flight path, speed, and altitude changes can be followed on FlightRadar24.  The radar track shows that thePiper Turbo Lance N26402 aircraft made at least one 180 degree turn, but then resumed its course.  

It wasn’t long too long after that the pilot found himself in trouble. The radar data shows the aircraft’s speed building excessively and its altitude dropping fast.  The made two mayday calls (recording below) before the aircraft crashed, killing all aboard.

The flight conditions were ripe for airframe icing.  The Piper Lance lacked deicing equipment.  Airframe icing changes the aerodynamics of the wing and tail and can bring an aircraft down in a matter of minutes.  The loss of control can be especially dramatic when it is the tail surface that ices up first.

 

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The SkyLife Bell 407 air ambulance helicopter departed from Porterville Airport at 6:52.  It crashed minutes later, halfway into its 50 mile flight to San Joaquin Hospital in Bakersfield.  The four aboard SkyLife Helicopter Crashwill killed, including the patient being transported.

The flying conditions at Porterville were acceptable.  Though it was dark, the weather was 3300 overcast, with light rain, light winds, and 9 miles visibility.  Under those conditions, the crew could fly “VFR,” meaning they could avoid terrain and other aircraft by simply looking out the windscreen.  Were the conditions significantly worse, the pilot would have had to fly “IFR,” and would have had to rely on instruments and help from air traffic control.

The helicopter crashed east of McFarland.  The airport nearest the crash site does not have weather reporting equipment.  But first responders say that by the time they arrived it was raining hard. Photos of the crash area show dense ground fog. 

 Heavy rain, by itself, does not necessarily pose a safety risk.  But the restricted flight visibility that generally accompanies heavy rain or fog, does.  A helicopter pilot who inadvertently wanders into clouds, fog, or heavy rain can quickly become disoriented and lose control of the aircraft . 

One challenge of night flying is seeing and avoiding poor weather conditions before you wander into them.  Inadvertent flight into clouds is called “continued VFR into IFR conditions.” Sometimes pilots, trying to stay out of the clouds, will fly lower and lower until they strike hillsides or power lines that are hidden in the darkness.  The results of that sort of “CFIT” accident are almost always fatal.

It’s too early to say if weather was even a factor in this case.  After all, the first responders who reported the poor conditions didn’t get to the site for more than an hour after the crash.  But ground scars should provide clues to whether the helicopter might have crashed because the pilot lost control or whether, instead, he struck the ground, wires or a radio tower that he could not see while in controlled flight.  

Investigators will also want to know whether the air ambulance crew had night vision goggles available to them.  Night vision goggles have been a hot button for the NTSB for some time. 

A few days ago, most were saying it’s too early to tell what brought down the Russian Airbus that crashed on Egypt’s Sinai Peninsula, killing all 224 aboard.  Now, there’s talk of the aircraft being downed by a bomb.  

Why a bomb?  The best explanation comes an article written by former NTSB investigator Doug Herlihy, appearing in the Goldendale Sentinel:

First, it’s likely that the aircraft came apart in flight.

The pieces of aircraft and persons on board are being found spread over 20KM (over 15 miles) in the mountainous region of the southern Sinai. The spread of wreckage is the most critical piece of the accident puzzle.    

When aircraft break up in flight, the parts are spread by two phenomena: the “ballistics” of the pieces and the wind.  “Ballistics” refers to the shape and weight of the object (like bullets or feathers) and how they will fly to earth.  The second factor is the wind at various altitudes as the parts fall to earth.  Like tearing a pillow in the wind, the parts are widely spread.

Second, aircraft seldom blow up because of a defect lurking within.  History shows that they almost always blow up because of an outside force.

Rarely, have any system or fuel supply or tank ever exploded a modern airplane.  Jet aircraft jet fuel, like kerosene and diesel fuel is not prone to explosion.  And, though it is not uncommon for an airliner to be hit by lightning, it’s almost unheard of that it has caused an explosion. Investigators know that either an on-board bomb or a hit by an explosive device is very high on the list of clues to search for.

NTSB preliminary reports do not draw conclusions as the cause of a crash.  But the NTSB’s preliminary report of the Turbine Otter crash that killed 9 near Ketchikan on June 25 suggests a weather-related “CFIT” crash, exactly as described here.

First, the report indicates that the flight was conducted under Visual Flight Rules.  That means that that pilot was supposed to stay out of the clouds and avoid the terrain by looking out the window rather than by relying on instruments.Chelton disply

Second, the report indicates that the closest reported weather was “marginal” for flying under visual flight rules.    (“The closest weather reporting facility is Ketchikan Airport (KTN), Ketchikan, AK, about 24 miles southwest of the accident site. .  .  few clouds 800 feet, broken clouds 1,200 feet, overcast clouds 2,700 feet. . .”) 

Third, and most significantly, a helicopter pilot searching for the aircraft minutes after the crash was unable to get to the crash site because the terrain was obscured by clouds and fog.  

The NTSB noted that the Otter was equipped with a moving map display that is designed to depict the aircraft’s position with respect to hazardous terrain.  When first introduced, such displays were seen as a boon to safety, making it easier for pilots to avoid terrain that they might not otherwise be able to see.  But some argue that such technology doesn’t increase safety at all, because pilots use the technology to fly closer to the edge than they otherwise would.  The phenomenon coming into play is called “risk homeostasis.” And in fact, the NTSB has previously found that aircraft equipped with moving maps and the other technology comprising modern "glass cockpits" have a higher rate of fatal accidents than those that aren’t.

We don’t know much yet about the plane crash in Alaska that killed the pilot and 8 tourists from the MS Westerdam.  But the crash looks eerily similar to the Alaskan crash that killed Senator Ted Stevens and three others in 2010.

Like the plane that was involved in the Westerdam crash, the plane that crashed with Stevens Otter Senator Stevens Crashaboard was a de Havilland Otter retrofitted with floats and a turboprop engine. Both tour pilots encountered adverse weather that is common in Alaska:  Low Ceilings. Fog. Gusty winds.  

In the Steven’s crash, instead of turning around when he encountered the low clouds, the pilot pressed on.  Unable to see where he was going, he inadvertently flew into the side of the mountain. (The local papers were calling the pilot a "hero" because not everyone aboard was killed. I had to disagree.)

In last week’s crash at Ella Lake, the weather conditions were similar.  It looks as though the pilot,Promech Air Otter employed by tour operator Promech Air, inadvertently flew into the clouds and struck the side of a cliff.  

This sort of accident is not uncommon, particularly in Alaska and Hawaii.  The type of accident is called "controlled flight into terrain."  It is almost always due to pilot error. 

Blue Hawaiian helicopters was probably the last tour operator that flew a perfectly good aircraft into the side of a mountain due to low clouds.  Compare the photo of the weather conditions that contributed to the Blue Hawaiian crash (left) with the photo of the weather conditions that the Promech Air pilot tried to fly through.  Note how, in both photos, the clouds obscure the mountain tops.

Otter Crash near Ella Lake Alaska weather