Accident Review: Pasadena PD Helicopter Collision — The Runway Centreline (original) (raw)

I remembered seeing this video a couple of years ago and at the time, I was curious to understand why it happened. So, I had a look around the Internet to find some answers and I satisfied my curiosity at the time. But it still seems the lessons from this accident aren’t widely known. So, here is my little attempt to take some lessons away from this very scary event.

Just the Facts, Ma’am

Just before 1600 (local) on the 17th November 2012, two Pasadena PD helicopters were operating at their heliport in California. N96BM, a Bell-Jet-Ranger-style helicopter, was pushed out of its hangar in preparation for a flight. At around the same time, N911FA, a similar model helicopter, was approaching the heliport to land after encountering some bad weather.

The pilot of 1FA noted the presence of 6BM on Pad 1 and after coming to a hover over the “main pad”, she turned left to air-taxi to Pad 2. With rain on her windscreen, the pilot manoeuvred the helicopter on to Pad 2 using its markings to ensure her aircraft was within the Pad boundaries. Once she was happy with her position, she lowered the collective and then the “sky fell.”

The main rotors of the helicopters collided. This transferred the considerable rotational energy in the rotors through to the aircraft transmissions, fuselages and even, the poor person that was at the door of 6BM talking to the crew.

Very luckily, there were no fatalities in this incident but there were minor injuries and extensive damage to two public-service aircraft.

The Culprit

It doesn’t look like the NTSB launched a full investigation but it did look into the event and produced a little overview of the results. Generally speaking, the NTSB identifies a range of factors and discusses numerous aspects of the accident on this page but on another, it makes, disappointingly, the following statement:

The National Transportation Safety Board determines the probable cause(s) of this accident as follows: The landing pilot's failure to maintain clearance with from obstacles a parked prior to landing helicopter and the other pilot's failure to park the helicopter inside of a marked parking pad. …

The fact that the first part of the sentence refers to the landing pilot’s failure is, I think, extremely misleading. But the statisticians will chalk up another accident to “pilot error” and move on. The rest of the sentence doubles down on the pilot blaming and throws the other pilot under the bus too.

But to what end?

CSI: Pasadena

Even with just that sentence and the video, you might start to see what happened here. The helicopter on the ground was not positioned within the bounds of Pad 1. So, when 1FA came into park on Pad 2, there was not enough clearance.

If we look at the pilot of 1FA and her decisions in isolation, I am hard pressed to identify an error. Especially, if one assumes that she is, indeed, human. As a police helicopter pilot, I can only imagine what the general level of pressure is in the normal day to day operation. Throw in some terrible weather with a big football match and any pilot’s cognitive load (how much thinking they have to do) is getting pretty serious.

Obviously, in aviation safety we already understand this. We have created systems to help humans deal with level of information. We have checklists and procedures and radios and additional crew and warning systems and navigation aids and so on and so on. The system is complex and no one person ever really has the ultimate responsibility. We rely on other people doing what they should to help keep us all safe.

As she approached to land, the pilot of 1FA noted the presence of 6BM on Pad 1 and did what she should have done - flown for Pad 2. She did even more that this. She called on the radio to see if there was a conflict with her intentions and received no reply.

But the other helicopter was not on Pad 1. Well, not completely. Due to ponding water, the pilot of 6BM had pushed the helicopter out on to the slighter higher ground of Pad 1 but now, his helicopter infringed the boundaries of Pad 2. Throw into the mix a spinning rotor and low visibility and what was the pilot of 1FA to do?

Acquittal?

So, do I think the pilot of 1FA is completely free from blame?

Yes.

I think she did what the system expected her to do and the system let her down. And before you comment below that a good aviation system is blame-free (or at least just), think about what the NTSB’s quote above says and compare that to the definition of blame.

The Real Culprit

So is the real culprit the other pilot that infringed the other pad’s boundaries?

Well, now I am going to “cheat” and say that I think we shouldn’t even be looking at pilots actions in such isolation. The other pilot made a decision and took action on a somewhat logical basis - the ponding water and the proximity to the fuel farm - and that he had seen other pilots do it. There is a systemic issue here.

And to their credit, the Pasadena PD did look into the design of the helipad and made some changes. They requested the Californian Department of Transportation to inspect their heliport. The resulting report outlined a number of deviations from established FAA guidance material and the Pasadena PD took a number of steps and responded.

The real culprit in most incidents, serious incidents and accident is, in my opinion, the system. And as such, our investigations need to look at and make recommendations on the system.

Safety Management System Improvements

I am pleased to note that the Pasadena PD at least acknowledge this in a small way in their response to the NTSB. I can’t quite see if the NTSB looked into the operator’s Safety Management System (SMS) but, apparently, on their own, the Pasadena PD identified the need to, among other things:

I think these are the real keys to improving safety. We don’t know exactly where the next incident or accident will occur but if we have a healthy system for identifying hazards and dealing with them, we give ourselves a chance of staying ahead of the curve.

Knowing When to Stop

Criminal investigation tends to stop when you have a culprit and sufficient evidence to lead to a prosecution. Safety investigations are a lot different. In this incident, there is plenty of evidence of things not going right in the video and scattered all over the accident scene. But I would have liked to see the official record of the investigation go a little further into the systems of the operator.

When conducting internal investigations, please remember to go this extra step. Too often, our systems set people up to fail and if we don’t address the systemic issues, another person will line up to do what we do best - be human.

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