Medical Helicopter Crashes into Radio Tower! The Story of Bayflite N428MB
The date is August 25th 2000, in beautiful St. Petersburg Florida and the weather is absolutely stunning. It's just after noon and a Eurocopter BK117 flown by Bayflite out of St. Joseph Hospital, crashes into a radio tower 500 feet above the ground. How could this have happened? Did the pilot lose situational awareness? And how may noise complaints by homeowners on the ground have led to this incident? Let's dig in....
Before we get too far into this story I want to re-emphasize the purpose of this story and that is to look at the data. To look at the information related to this type of incident in hopes that you or me, or anybody else can learn from this incident in order to be safer in the future. This story will deal with the loss of life and while I can understand the emotion that may go along with that I also have to respect the lessons that can be learned from such an incident.
This helicopter was a BK117-A3 and was manufactured by Eurocopter with a total number of flight hours of 6,642. The last inspection of the aircraft was completed on March 15, 2000. In the world of medical helicopters, especially back in 2000, the BK117 was akin to the Ferrari of helicopters.
The BK was a very large aircraft for medical helicopters, had two 600-horsepower turboshaft engines, and the medical compartment pretty much resembles the back of an ambulance. With many medical helicopters being very cramped, the BK had room to move around and even has a full size stretcher with rear doors to load the patient. This was, and still is in many areas, a very sought after helicopter to fly on. It had tons of power and tons of room, was very well made, and was very safe.
This pilot was a very experienced pilot even though he was just 38 years old. He held a class 2 medical certificate, and was rated for helicopters and instrument flight. He had a total of 4,367 hours of flight time with 169 hours on type (BK117). He was hired by the parent company, Rocky Mountain helicopters, about 1 year prior to the accident on July 17, 1999. The pilot did have lots of experience flying in the Tampa Bay area as he had worked for several local news companies flying helicopters for nearly 15 years.
The crew was at St. Joseph's Hospital on the morning of the accident, when at 10:05 in the morning they received a call for a scene flight in Pinellas County on the other side of Tampa Bay. Tampa Bay is a very densely populated area surrounded by lots of waterways and while the flight times may be very short for medical helicopters, they save an awful lot of time on ground transport due to heavy traffic in the area. After going en route at 10:05 it took the crew just 10 minutes to fly across Tampa Bay and land at the scene. The crew were on scene for just a bit over 7 minutes, and at 10:22 they departed the scene, taking them only six and a half minutes to land at Bayfront Medical Center on the southside of downtown St. Petersburg. The crew landed at Bayfront Medical Center at 10:28 a.m. where the medical crew went inside and transferred patient care to the hospital staff. The crew stayed at Bayfront for nearly two hours which is not uncommon as they would have needed to restock their aircraft, may have stayed for lunch, or may have been participating in patient care in the emergency room during this time. At 12:12 p.m. in the afternoon the crew departs Bayfront Medical Center in St. Petersburg to return to their base at St. Joseph Medical Center in Tampa.
Just four minutes after taking off from Bayfront Medical Center and headed towards their home base at St. Joseph's Medical Center, Bayflite 3 collided with a nearly 700 ft radio tower over the Weedon Island Preserve Nature Park just north of St. Petersburg. After hitting the guy wire, and the tower, the helicopter spun out of control as its rotor blades flew off in different directions with the main fuselage of the aircraft landing roughly 300 feet north of the tower in a very muddy mangrove swamp.
The tower itself also completely fell just after the helicopter hit the ground and was completely destroyed. Sadly the pilot, the flight paramedic, and the flight nurse were all killed and did not survive the accident.
This radio tower was built and completed in 1977 and was used to broadcast AM and FM radio signals across western Florida. The tower did have an omni-directional strobe on top of it which was shown to be in working order. The entire structure did fall right in the vicinity of the accident. Further examination of the tower revealed that there were several fresh impact marks at the 480-foot level of the structure. This accident, along with many others, helped to pave the way for the broad implementation of terrain awareness warning systems or TAWS, to be installed on medical helicopters. TAWS is a system that provides the pilot with sufficient information and alerting to detect a potentially hazardous terrain situation, such as a radio tower, mountain, or even a tall building, and so the pilot may take effective action to prevent a dangerous event that we call a “controlled flight into terrain.” This system is what you may have heard in movies where right before an aircraft may crash you hear “obstacle ahead” or “pull up” Throughout aviation history, and especially before the implementation of TAWS, there have been many fatal accidents that were caused by controlled flight into terrain. While TAWS was not required at the time of this accident, it is now a requirement for all medical helicopters in the U.S.
It is also worth noting that this helicopter was equipped with a wire strike protection system which consists of a mechanical wire cutter, usually above and below the fuselage, that is designed to cut electrical power wires should the aircraft fly into them. So, why did they not work in this case? Well, the wire strike protection system is designed to cut wires that are basically perfectly perpendicular to the flight path of a helicopter. In this situation, the guy wires for this radio tower were at too much of an angle to be able to be cut by the wire cutter on the helicopter.
Now, remember what I said about this area being very densely populated and bordered by waterways in all kinds of different directions? On top of that they are also somewhat limited by several large international airports, as well as the very busy MacDill Air Force Base on the south side of Tampa. One might think that to return to St Joseph’s from Bayfront Medical Center that they should simply fly across Tampa Bay as that would be the quickest route, right? Well, when it comes to helicopters, in general, most aircraft would normally want to avoid being out over open water in case of an engine failure or a mechanical failure as this would give them the option to be able to land the aircraft if they could find a suitable spot on the ground. This is not possible if you are out over open water and contrary to what many people may first think, aircraft such as helicopters sink quite a bit faster than you would believe, giving the crew very little time to escape should they need to. So, it is far more common for aircraft, especially helicopters, to fly along the coast where they may still be over the water but if they need to they can still land on the ground or on the beach or possibly even in shallow water and still have a chance to walk away from the accident. Bayflite is a very busy medical helicopter service and they had several bases around the Tampa Bay area and landed in downtown Tampa and downtown St. Petersburg quite often and would refuel at Albert Whitted Airport routinely. Just a few days before this accident happened, Bayfront Medical Center was receiving complaints from homeowners in the affluent neighborhood of Snell Isle, just on the northeast side of downtown St Petersburg, that Bayflite was flying too low and the noise was bothering them. Bayfront Medical Center had passed along this information to Rocky Mountain helicopters who advised their pilots to seek alternate routes when flying north over St. Petersburg. There was no specific policy on what route to choose and the route was left to the discretion of the pilot in command with many of the pilots electing simply to fly a little bit further out over the water. But that was not the case on this day. Instead, the pilot chose to fly slightly west of this neighborhood on a more northerly route and then turn east when they got closer to the Gandy Bridge on the south side of Tampa Bay.
The National Transportation Safety Board (NTSB) found that the probable cause of this accident was “The pilot's failure to maintain clearance that resulted in the in-flight collision with a tower." Rocky Mountain helicopters was very adamant at the time that “this accident was not caused by a lack of information concerning [the tower] or other obstacles” as the obstruction had been there for 23 years and the pilot had been flying in this area for other companies for nearly 15 years.
So, why, on a clear and beautiful day, with a perfectly functioning helicopter, with an experienced pilot, did they crash into this tower?
Well, there was a new navigation system that had recently been installed in this aircraft called an AARNAV MFD GeoNet Datalink system. While the report does mention that this system was new to the aircraft and that the pilot had used this system before at a previous employer, it has been suggested that the pilot, and possibly the paramedic as he was also seated in the front, was working with this system, possibly distracting them and causing the pilot to lose situational awareness and crash into the tower.
The pilot would have most definitely had a loss of situational awareness causing him to be distracted. Situational awareness has been studied extensively in many high dynamic professions such as commercial aviation, space flight, surgery, and paramedicine. Much of what we know about situational awareness stems from many aviation accidents that happened in the 1970s and 1980s, especially including Eastern Airlines flight 401 where a perfectly good Lockheed Martin L1011 crashed in the everglades outside of Miami, FL while the pilot, co-pilot, engineer, and mechanic were distracted while fiddling with a burned out light bulb that they thought meant their front landing gear was not down. This crash killed 101 of its 176 passengers and helped to pave the way for theoretical models such as situational awareness and new concepts such as crew resource management (CRM). While not a requirement back in 2000, CRM is now required of all medical helicopters including the medical crew as they are considered a part of the crew and are not attendants as some services used to call them.
Likewise, breaking from routine may also have played a role in this accident. This pilot, and this crew, were used to flying back to their home base in Tampa by flying over the eastern coast of St. Petersburg but, now - due to the noise complaints - were now flying a different route. While the pilot may have been familiar with this other route, it was still a break from his regular routine. As I mentioned in a previous story regarding a medical helicopter that crashed after running out of fuel, a study by Sarter and Alexander done in 2000 specifically discusses that many errors of distraction may stem from lapses of attention stemming from the interruption of a task by someone in the cockpit and then subsequently forgetting to perform an overlooked action. In this case, it is possible that the pilot, and possibly the paramedic, were distracted by a new piece of equipment in the cockpit, thereby causing the failure to avoid a known obstruction in a somewhat routine flight path.
This accident, while absolutely tragic, also helped to pave the way for certain changes in helicopter EMS in the United States. TAWS is now requried on all medical helicopters. CRM is also now a requirement of all medical helicopters which allows all members of the crew, including the flight paramedic and flight nurse, to be a part of major safety decisions and speak up, without the fear of retaliation or reprimand, when they feel a safety issue has occurred.