Kobe Bryant Accident. Two Weeks On....What Does The Preliminary NTSB Report Tell Us?
They say a week is a long time in politics, and a fortnight is almost a lifetime. It’s now been two weeks since the fatal helicopter crash in the north Los Angeles hills that resulted in the tragic loss of a helicopter pilot and his 8 passengers. At the time, like many in the Helicopter Industry, I was in LA preparing for the Helicopter Association International’s annual Heli Expo gathering – the largest rotorcraft exhibition in the world. The accident cast a shadow over the week’s proceedings, and, as you can imagine was a hot topic of debate on the Expo floor during the working day and, at least amongst pilots, in the bars afterwards.
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In the immediate aftermath of the accident I urged caution to those from the media seeking an instant answer to the questions “why?” and “how?”. The first few hours post-incident are critical to both securing physical evidence and eyewitness testimony; speculation by those not directly involved risks tainting the latter, and, perhaps setting the public on a pre-determined causal outcome. Why did I urge caution so strongly? To a degree, there’s a professional courtesy to the pilot involved. Whilst the weather seemed likely to play a significant part in the accident sequence, there remained the distinct possibility that it was an aggravating factor on top of an even greater emergency confronting the pilot. There remained the distinct chance that the pilot would be blamed before all of the evidence was examined. I wanted no part of such a “Kangaroo Court”.
There might have been a catastrophic structural failure in the aircraft. The tail boom may have sheared off, or, as in a recent accident involving an Airbus EC225 Super Puma, the entire rotor assembly may have detached from the airframe. If either of these catastrophic failures had afflicted the aircraft, there was nothing the pilot could have done – they would also have explained the lack of radio call and sudden, rapid, height loss that was reported on flight following websites such as Flightradar24. Less catastrophic than a structural failure, but made significantly worse by terrain and weather, the pilot may have been confronted with a tail-rotor drive or gearbox failure. For non-helicopter pilots, the immediate actions upon diagnosing a tail-rotor failure is to remove the torque in the transmission systems by lowering the collective (‘lever’) quickly. At low speeds, for example attempting to turn around in terrain or trying to ‘grovel’ through bad weather, a tail-rotor failure will announce itself with a dramatic undemanded yaw (motion of the nose to the left or right, depending on the rotation direction of the main rotor) and, likely, some form of mechanical noise and a plethora of warning tones in the cockpit. At low speed recovery is difficult or aerodynamically impossible – exemplified by the ‘worst case’ tail rotor failure suffered by the crew of the Leonardo AW169 carrying the owner of Leicester City FC out of the King Power Stadium post-match in October 2018. A tail rotor control linkage failed as the aircraft was in the high hover turning onto a departure heading leaving the crew with no aerodynamic effect to exploit and resulting in a spinning, high rate of descent, impact with the ground, killing all 5 on board. An in-flight fire could also result in a rapid descent to the ground. The pilot may, if it’s an engine fire, rapidly descend and land if the engine extinguishers don’t put the fire out quickly – it can become a “boldface drill” in the checklist as a “Land Immediately”, regardless of obstructions and terrain.
Both a tail rotor failure and uncontained fire may also leave witnesses confused on the ground to what they have seen and heard. The act of rapidly lowering the Collective to initiate a rapid descent will cause a marked change in engine note and, if combined with a manoeuvre, cause airflow to detach off the rotors causing a ‘bladeslap’ effect which may well sound like ‘sputtering’ to those below. Furthermore, shutting down the engines to assist with the autorotation and prepare for a emergency landing will also cause the aircraft’s noise to change. Finally, let’s not discount that any sort of noise in mountainous terrain can be distorted via reflection off hillsides.
Therefore, in the immediate aftermath of the accident, I think there was enough doubt to the possible cause to belay any compulsion to leap to apportion blame to the pilot.
I understand that, with a high-profile celebrity on board, the accident has significantly more exposure than the norm, and that the wealthy, the powerful and the simply enchanted all want to know how this tragedy struck their friend, teammate, icon or hero.
The pilot was also important to many people, and he deserves the due process to be followed. Most importantly, other aviators and potential passengers need the facts not the emotional hyperbole to make better informed decisions in the future.
The lack of urgent Airworthiness Directives issued by the FAA, EASA and the manufacturer, Sikorsky, after some two weeks of investigation by the NTSB is a strong indication that nothing clear and obvious has been discovered in the initial investigation. No ‘smoking gun’, such as a detached rotor, snapped tail rotor drive shaft or irrefutable evidence of pre-impact fire, has been found. Indeed, the preliminary report issued by the NTSB provides no hint that mechanical failure is expected to be identified as the primal cause. This puts the accident into the ‘other causes’ box and means we will have to wait for a definitive assessment – if one is ever arrived at. A wait and determination not helped, of course, by the lack of Cockpit Voice Recorder (CVR) or Flight Data Recorder (FDR) – colloquially known as the ‘Black Boxes’. The lack of CVR will likely prove key in this accident. The CVR provides not only the recorded voice of the pilot, but also the ambient noise in the cabin – which can often alert investigators to changes in engine/transmission noise or discussion between the pilot and the passengers.
Two high-profile non-CVR equipped accidents in the UK have resulted in continuing uncertainty over why the pilot(s) did what they did and made the decisions they made.
Firstly, the Mull of Kintyre Chinook crash, in 1994, has many resonances with the loss of this S-76B. Both aircraft were flying important people (the Chinook was carrying key Special Forces and Intelligence staff), both were not fully Instrument Flight Rules (IFR cleared) and both flew into terrain at high speed in poor weather. The UK MoD conducted its investigation, yet Senior Officers elected to overrule the Incident Board’s conclusion of “Cause – Not Positively Determined” and impose one of Gross Negligence upon the pilots. Evidence slowly emerged over the course of the next 15 years that showed there was significant airworthiness concerns over the aircraft; ones that may have sufficiently distracted the pilots to cause the accident – concerns that could not be confirmed nor assuaged with the evidence of a CVR. As a result, both pilots were later exonerated.
Secondly, a good friend of mine was killed when his Police helicopter suffered a double engine flameout and crashed into the roof of the Clutha Pub in Glasgow one night in 2013, killing the rest of his crew and 7 drinkers in the pub. Without a CVR it proved impossible to determine the pilot’s thought process leading up to a mismanagement of the fuel system which left the aircraft crashing through fuel starvation, despite having enough fuel in the tanks to recover to base.
This discussion of ‘other causes’ also brings us to the seemingly benign and yet potentially insidious and shines an uncomfortable light on Human Factors.
It is a well-established fact in aviation that Human Factors account for some 80% of all aviation accidents. Factors include bad supervision, pilot error, deliberate disregard for regulations or poorly conducted maintenance. Human Factors also includes the work of Air Traffic Control and other agencies.
Although equipped for 2 crew, Ara Zobayan was flying the S-76B that day as a single pilot. In a normal California day of clear skies, it is completely understandable why the aircraft would be crewed this way – it reduces the cost of using two pilots and increases payload/fuel available. However, when the weather is bad, pilot workload increases dramatically. If Ara had been confronted with an emergency in the cockpit he would have been inevitably distracted – his eyes would have stopped scanning the outside world and looked inside to diagnose and deal with it. Even if he’d not suffered a minor emergency, in complex weather conditions, going ‘heads-in’ to simply change a radio or navigation aid frequency, adjust an altimeter setting or any number of other cockpit husbandry tasks can lead to vital seconds spent not assimilating the cues from the real world. Ara may well have gone heads-in whilst clear of cloud and looked up to find himself in it. The ‘what happens next’ is of vital importance.
Perhaps unsurprisingly, a series of long-scheduled ‘Inadvertent IMC’ (IIMC) classes (effectively, flying into cloud without notice or planning to do so) at Heli Expo were packed with aviators and, one suspects, some non-rated journalists as well. In them, Police pilot Bryan Smith raised a number of agonisingly pertinent points about the Human Factors behind IIMC. Some of these are difficult to hear as a pilot, but, nonetheless they need a broader audience.
Firstly, my instinct as an ex-military aviator was “why didn’t the pilot just IFR abort?” and climb to a safe level either clear of cloud or in cloud and above Safety Altitude (SALT) - a height that is calculated to account for nearby terrain and any errors in instrumentation. I’ve done this several times when confronted with low cloud. But then I was Instrument Rated, flying a machine that was IFR-certified, with a co-pilot and rearcrew to help and flying a machine in the CH-47 which invariably had a enough fuel on board for an IF Diversion – i.e. the fuel to climb, fly to an airfield, complete an Instrument recovery and land, plus with margins for holding and a Minimum Landing Allowance. The only thing to bear in mind for me was the potential for icing and the risk of climbing up into Controlled Airspace (CA). Ara certainly didn’t have icing to worry about in SoCal, but he did have to consider CA if he pulled up. I’ve pulled up into CA. We had time to compose ourselves, pre-set the Transponder to the emergency code, guaranteeing we would appear flashing on ATC’s screen, and set the expected contact frequency on the radio, and also selected the GUARD frequency we would use to pass the Mayday call on. We had come to a halt in a valley in France and creeping forward at 20ft below the wheels wasn’t getting us anywhere. We prepared and punched up. As soon as we got clear of terrain we were contacted on GUARD before I’d even got the Mayday call out – I’d been focussed on the instruments and applying the old adage of pilots – “Aviate, Navigate, Communicate”. ATC rapidly identified us and gave us a heading to steer and flight level to climb to. We cancelled the emergency, filed an IFR Flight Plan and continued to our destination.
Why didn’t Ara do the same? It’s, ultimately, the $64,000 question.
Firstly, we will never know with certainty. However, Bryan Smith noted that accepting the situation you’re in is key. Trying to maintain Visual Flight Rules (VFR) whilst ‘scud-running’ along the cloud base in terrain is difficult. The temptation if suddenly enveloped in the cloud is to descend and turn around. Smith, wisely in my opinion, suggests that this is the worst possible thing you can do. Turning and descending whilst not fully committed to instruments leaves the pilot betwixt and between – committed to neither IFR nor VFR techniques and trying to cobble together some form of a compromise on the hoof. Smith’s advice is clear – if you get caught out, commit to the instruments, get above terrain or on top of cloud and then have a think. Talk to ATC only once the aircraft is safe and get them to help you. Smith also noted that the majority of IIMC accidents occur within 2 minutes – either disorientation and loss of control or Controlled Flight Into Terrain (CFIT).
Ara might have had options. Yes, it might have been professionally embarrassing to pull up into CA, but at least he was already talking to ATC so it would have been less fraught than my experience in France. Pulling up, however, would almost certainly force him into an Instrument approach back at John Wayne or into Van Nuys. This would have imposed a significant delay into the schedule of his passengers, as would have been his second option, to request Van Nuys for a Special VFR join, land, and wait for the fog to clear or hire ground transportation.
Yes, it would be inconvenient. But they would have completed their journey. But, then again, hindsight is 20/20. Ara may well have successfully flown a similar route in similar conditions in the past – providing increased confidence that he could fly the same profile again.
The facts we know are sparse; they launched in weather that was at best ‘on limits’ – and bad enough for most other helicopter operators to cease operations awaiting improved conditions – they flew under the cloud, exploiting the valley system to stay clear of the cloudbase, but which caused significant delays as they were held for Van Nuys traffic before being cleared. Perhaps the delays were playing on Ara’s mind; professionally, of course, he wanted to get his client to his destination on time. He tried as hard as he could to keep his contract, but, ultimately, a combination of terrain, weather, cockpit workload, possible perceived pressure and air traffic conspired against him it seems.
Ara was not the first helicopter pilot to come to grief in the hills in bad weather. Sadly, he’s also unlikely to be the last.