Archive for February, 2012

IMC encounters

Friday, February 24th, 2012

Using a simulator, researchers at the University of Illinois conducted a study with 20 pilots who had no instrument training to see the survivability of an encounter with IMC conditions. All of them lost control, and the only variable was how long it took. The range was as short as 20 seconds to as long as 480 seconds with the average being 178 seconds. This was done in a fixed-wing simulator and I do not know of a formal study like this done with helicopters. My guess is a helicopter pilot with little or no instrument training would lose control in a much shorter time. Continued VFR flight into IMC conditions has caused many helicopter accidents.

For example, according to the National Transportation Safety Board a Bell Jetranger and an R44 helicopter were in route to Astoria, Washington when they encountered an overcast layer. A passenger in the Jet Ranger reported that the pilots of both helicopters were in continuous contact during the flight and as the weather conditions deteriorated, the pilot in the accident helicopter asked the pilot in the Jet Ranger what they should do. The witness reported the pilot in the Jet Ranger stated, “I’m going to go through it, stay right behind me.” The pilot in the accident helicopter agreed. The witness reported that when the Jet Ranger entered the fog, the accident helicopter was behind and above us. Approximately 30 seconds later; the pilot of the Jet Ranger stated, “Go back up… it’s too low. It’s much lower than we thought. Go back up right now.”

The witness stated that as the Jet Ranger ascended, the pilot attempted to contact the accident helicopter, however the attempts were unsuccessful. The Jet Ranger departed the area and was eventually able to land in Astoria. A search for the other helicopter was initiated and two orange life vests and miscellaneous debris were located floating in the water. The bodies of both pilots and passenger were recovered in the general area later that day. Numerous smaller pieces of helicopter wreckage were recovered from the water; however the majority of the wreckage was not located.

The pilot of the R44 held a commercial pilot certificate with rotorcraft-helicopter and instrument ratings. The pilot also held a flight instructor certificate with helicopter and instrument helicopter privileges. As an instrument instructor I am sure the pilot had practiced instrument flying with a vision restriction device. However, there is a significant difference between practicing with a hood and losing all visual references while under stress.

HEMS history

Tuesday, February 14th, 2012

Most people remember the TV show MASH. Set during the Korean War, it featured patients being flown into a Mobile Army Surgical Hospital (MASH) with Bell 47 helicopters. In the beginning of the conflict the helicopters would occasionally pick up wounded soldiers when not busy with other missions. When doctors started noting that the survival rate increased when patients were transported by air, the Army took notice. The military started dedicating helicopters to medevac missions and when the Korean War ended over 22,000 wounded troops were transported by helicopters resulting in a lower mortality rate than previous wars. The Army further developed this concept with the Vietnam War by adding more sophistication, like in-flight medical care. Mortality rates continued falling and during the course of this conflict more than 800,000 wounded soldiers were transported.

Many returning military personnel understand the advantages of transporting trauma patients by helicopter first hand and starting applying these concepts to the civilian world. In 1970, the Maryland State Police Air Unit transported the first trauma patient by helicopter. Two years later the first hospital based helicopter program was launched at St. Anthony’s Hospital in Denver, Colorado.  By 1980, there were roughly 32 hospital based programs flying about 17,000 patients a year.

At this point the HEMS (Helicopter Emergency Medical Service) was a proven concept and the industry began to really organize. Medical interiors started getting more sophisticated and standards, guidelines and training programs for crew members were developed. By 2000, the number of programs had grown to 231 operating over 400 aircraft. Today, there are over 300 air medical programs operating about 900 helicopters.