Friday, October 18, 2013

BASH BAM BOOM... Living Through A Bird Strike

NTSB Identification: ERA14CA009
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Sunday, October 20, 2013 in Madison, MS
Probable Cause Approval Date: 12/19/2013
Aircraft: EUROCOPTER AS 350 B2, registration: N911ES
Injuries: 3 Minor.

According to the pilot, he was climbing the helicopter through 1,300 feet when he felt an "explosion" in his face that knocked his visor up and affected both his visibility and crew communications. The pilot was eventually able to get his visor back down and land the helicopter, where it was discovered that both windshields were blown out, the center post and the cabin shell were damaged, the doors were blown open and on board medical equipment was missing. On the ground, a crew member stated that just before the event, he had seen a black bird fly toward the helicopter from above and left, but did not have enough time to call it out. Analysis of on board residual bird feathers and a photograph of the suspect bird carcass indicated that it was a black vulture, which can weigh up to 4.8 pounds.
The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The helicopter's collision with a black vulture during climb to cruise altitude.

BASH (Bird Aircraft Strike Hazard)  

BAM (Bird Avoidance Maneuver) 
BOOM (the sound of your windshield exploding in your face - keep your visor down and your guard up) 

During shift briefings, I like to question the crew members I will be flying with about proximate threats - what will kill us today.? In a single-engine helicopter, engine failure comes up a lot. In fact, a bird strike is much more likely than an engine failure, and can be just as deadly.

On January 4, 2009, a Sikorsky S-76 helicopter hit a Red-tailed Hawk in Louisiana. The hawk hit the helicopter just above the windscreen. The impact forced the activation of the engine fire suppression control handles, retarding the throttles and causing the engines to lose power. Eight of the nine persons on board died in the subsequent crash; the survivor, a passenger, was seriously injured  

Some aircraft have plastic windshields, some have glass. The picture above makes clear that even a glass windshield will give way for a big enough bird. 

"A 12-pound Canada goose struck by a 150-mph (aircraft) ... generates the kinetic energy of a 1,000-pound weight dropped from a height of 10 feet." 

(Bird Strike Committee, Boeing Aero Magazine online at http://www.boeing.com/commercial/aeromagazine/articles/2011_q3/4/

During my initial training with Air Methods, we were told about a pilot who took a bird through the windshield, and then suffered a loss of power from both engines!  He pushed the collective down and entered autorotation, and as he neared the ground, muscle memory and pattern recognition led him to sweep his hand overhead from back to front to verify that his throttles were all the way forward to the "flight" position - something he had done thousands of times as part of his before-landing checks - and they weren't forward. The bird had pushed them to near idle. He shoved them forward and regained power for a "normal" landing. 

One of the hallmarks of safe flight operations is the identification of bad things that might happen, and the preparation for their eventual occurrence. We use drills, rehearsals, simulators, and table-talk to get ready for all sorts of unpleasant events, but how might we prepare for a bird coming in through the front window. Perhaps someone who has lived through it might be asked to speak at a safety meeting or group event, or write his or her recollection of the event for dissemination.

Several years back Dave Andrews, a HEMS pioneer, took a bird through the windshield of a BK-117 in South Carolina. This was before pilots flying EMS routinely wore helmets, and the bird knocked off his headset before going back out through the greenhouse (the small overhead window that allows pilots to see where they are going during a tight turn). He couldn't communicate with the crew in back at that point, and it must have been quite an adventure for them, waiting to find out their fate. The wind and noise in the cockpit must be disorienting - simply maintaining aircraft control and slowing down are probably hard with a pounding heart and a shaking hand, I have heard of crews having a hard time figuring out if the blood and loose parts in their faces belong to themselves or the bird.  

The numbers:

Experts within the U.S. Federal Aviation Administration (FAA), the U.S. Department of Agriculture, and the U.S. Navy and U.S. Air Force expect the risk, frequency, and potential severity of wildlife-aircraft collisions to grow over the next decade.
Between 1990 and 2009, bird and other wildlife strikes cost U.S. civil aviation more than $650 million per year.

About 5,000 bird strikes were reported by the U.S. Air Force in 2010.

More than 9,000 bird and other wildlife strikes were reported for U.S. civil aircraft in 2010.

Between 1990 and 2009, 415 different species of birds and 35 species of terrestrial mammals were involved in strikes with civil aircraft in the United States that were reported to the Federal Aviation Administration.

More than 219 people traveling by airplane have been killed worldwide as a result of bird strikes since 1988.

Source: Bird Strike Committee USA 

website http://www.boeing.com/commercial/aeromagazine/articles/2011_q3/4/

During the day, we can often see a bird coming, and make a gentle avoidance maneuver. Opinions vary on what sort of avoidance to attempt, A climb usually works as the bird will tuck and dive when frightened. Some birds seem to go into "attack mode" and turn into our path.

At night, striking a bird without warning is one of the most disconcerting events for a pilot and crew. I was between Douglas Georgia and the burn center in Augusta one night at three thousand feet when we hit a big bird. The BOOM was so loud it brought the patient up out of sedation with  "What was THAT?"  and so violent it knocked the gel-coat off the nose of our BK. Thank goodness it didn't hit a foot above - on the windshield. I tasted copper in my mouth for several minutes after.

After that event, I began to leave the landing light on during night flights. Research on the effectiveness of this technique is mixed, but for me it works - I haven't hit a bird since I began leaving a light on. I have always flown with my visor down since I began wearing a helmet for HEMS, but now I am flying at night with NVGs, and the only thing between my eyes and whatever comes through the windshield is a set of tubes...

Even rocket ships hit birds...

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