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Learning from Our Accidents
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The Accident That Started the NTSB
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I am fortunate to have a “rails to trails” walking path close to my house. A couple of times a week, I end up walking past the site of a horrific train crash that happened on December 5, 1921.
My walking trail used to be a single-track rail line that stretched from the northern Philadelphia suburbs to West Trenton, NJ. To let the outbound train pass, the other train had to pull onto the siding in Bryn Athyn, PA. This was done safely for decades but on the day of the accident, there was a third train.
The crew misread the instructions for the day that would have told them about the third train. Seeing a train on the siding and thinking the way ahead was clear, the outbound train kept going.
A mile and a half down the line, it collided head-on with the third train. The steam engine and kerosene lamps ignited the wooden cars, and many people who were trapped in the cars burned to death. The result was 27 dead and 70 injured. The conductor and engineer of the outbound train served time in prison for the accident.
This accident provided a lot of opportunities for improving the policies and procedures of the railroad, and it was the start of a fundamental change in how we treat transportation accidents. Although I can’t verify this online, the historical marker at the site says that this accident led to the formation of the National Transportation Safety Board (NTSB).
Today, the NTSB looks at all types of transportation accidents. For those in our industry, it makes recommendations to operators, manufacturers, and the FAA for safety improvements. In this issue of our newsletter, we’ll look at two products that come from the NTSB: an accident report and a hearing where the board discusses an accident in detail.
Over the years, I’ve had the pleasure of knowing and working with members of the NTSB and their staff. These dedicated folks set the professional standard around the world for accident investigations and have helped us to realize the many, many links in most accident chains.
Do you regularly read the NTSB reports about helicopter accidents to see if you can apply the lessons learned and make your everyday operations safer? You can learn a lot at ntsb.gov.
— Stan Rose
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Why Participating in SMS Matters
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Recently, the NTSB issued a press release that states that a January 2019 fatal accident in Ohio involving a helicopter operated by air ambulance operator Survival Flight was caused by that operator’s “inadequate management of safety,” which led to a pilot departing on a flight without a thorough preflight weather evaluation.
Although many more operational lapses on the part of the operator were cited in this inquiry, the bottom line is that Survival Flight did not manage safety properly and had a poor safety culture. Is this how your operation would be described if you had the unfortunate experience of having an accident?
Today, it is not an FAA requirement for Part 91 or 135 operators to have an safety management system (SMS). However, the NTSB cited as a contributing factor to the accident the FAA's "failure to require Title 14 Code of Federal Regulations Part 135 operators to establish safety management system programs."
Everyone who is involved in the safety and prevention business—insurance brokers, underwriters, regulators, OEMs, and the attorneys for plaintiffs—knows that SMS is an effective way to reduce the risks associated with aircraft operations.
If you ever—God forbid—find yourself in the hot seat being asked by a lawyer unpleasant questions about your safety management program, you can bet that lawyer will ask why you never bothered to take advantage of SMS, a safety program that has been endorsed by aviation regulators all over the world. "Why, oh why, didn't you take that step when you know that it could have saved lives?" I've been a witness in aviation accident trials, and believe me, this is no exaggeration.
On the regulatory side, the NTSB continues to recommend that the FAA require SMS and flight-data monitoring be implemented in all helicopter operations. We can assume that this pressure will build until we all have to comply. After all, our industry's accident rate is hard to defend, and accidents are expensive.
At this time, I ask that you take this opportunity to start managing the risks inherent in aviation. A good place to start is at your next safety meeting. First, read up on some SMS principles.
Next, start a conversation with your colleagues about what would be the most likely thing to cause your next big accident, the kind that puts operators out of business. Pick the top three. Then think of ways to prevent them from happening, and put those solutions into practice.
Boom! You just started your SMS program. Good luck, and keep going!
— Stan Rose
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faasafety.gov
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Helicopter Accident Review
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Disclaimer: We are using this accident report as a springboard for discussion and to pass on some actionable safety tips that might help you if you find yourself in a similar situation. We do not intend any disrespect for the pilot involved—we weren't there. In fact, because of this pilot's decision to land the aircraft, six people walked away from this accident, including two with minor injuries. You can read the NTSB report for all the details.
The accident aircraft was an Airbus EC130 operated as an air tour flight. While in cruise flight, the pilot noticed a significant, high-frequency airframe vibration. He said that as soon as the vibration started, the tail rotor chip annunciator light briefly illuminated. As the vibration continued, the tail rotor chip light "flickered." The vibration and noise stopped after a few seconds, and the chip light extinguished.
The pilot selected a large open area as a precautionary landing site and slowed the helicopter on approach. As the helicopter slowed, he raised the collective and applied right tail rotor pedal, but the nose of the helicopter veered to the left. The pilot noted that he eventually applied full right tail rotor pedal, but the nose of the helicopter continued to the left.
At about 200 feet above ground level, with the right tail rotor pedal fully depressed, the helicopter began to spin to the left. In an effort to stop the spin, the pilot attempted to gain forward airspeed. However, he eventually closed the engine throttle and performed a hovering autorotation. According to the pilot, the helicopter descended, touched down hard, and subsequently rolled on its right side, sustaining substantial damage to the fuselage, tail boom, and main rotor drive system.
An NTSB post-accident examination of the helicopter revealed that one of the 10 tail rotor fenestron blades fractured at the blade root, and it subsequently deflected off the fenestron drive shaft, creating an imbalance, which was followed by the failure of the drive shaft.
The Chip Light
Usually, when we get a tail rotor chip light, we do a precautionary landing. The presence of loose metal in the gearbox is an indication that something is failing. At this point, our goal is to safely put the aircraft on the ground before we lose tail rotor control.
Whether the light was on or off, there was already a “significant, high-frequency airframe vibration.” The light is an indication that something is about to happen; the vibration tells us that it has already happened. In this sequence, when a chip light is followed by a vibration, it's not a precautionary landing but an emergency landing. We should assume that we will lose the tail rotor before we get to the ground.
When to Land
The EC130 emergency procedure says you should:
- Adjust cyclic to Vy and control yaw
- Reduce collective to control side slip
- LAND AS SOON AS POSSIBLE!
If you can keep the yaw under control, it may look like it is OK to fly to a suitable location.
However, in this case, the vibration indicates that further damage may happen if you keep flying. I think you need to get it on the ground as soon as possible to prevent a catastrophic failure of the gearbox, tail rotor, or driveshaft.
Landing Profile
This pilot was making a precautionary landing and discovered, at the bottom of the approach, that he no longer had tail rotor control. At the point in time where he had to split the needles, I suppose that he did not make it to his point of intended landing.
This is an example where you should plan for the worst and hope for the best. Establish a power-off glide and plan to finish with an autorotation. Keep the engine engaged until you get to the bottom, and hope that you can use the power.
Bottom Line: If you experience a tail rotor failure in cruise flight
- Cyclic: Adjust to Vy and control yaw
- Collective: Reduce to control side slip
- LAND AS SOON AS POSSIBLE
- Carry out an autorotative landing to suitable area.
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