In April of this year I posted this photo taken by Deputy Rocky Laws, in the policehelicopterpilot.com photo gallery. It was a beautiful MD500 often seen flying in and out of Gillespie Field (our home base) in El Cajon Ca. I was sure that this photo captured by Rocky would be appreciated by any helicopter enthusiast, and since we fly MD's also, it was more than worthy of being included in the gallery.
I was sad to learn that this helicopter was involved in a fatal crash last week, (July 22nd) in Wharton Township Pa., while reportedly performing "long line" operations in support of natural gas survey work.
Early reports by the news media indicated that the line and basket underneath the helicopter may have become entangled in trees, and the pilot attempted to make an emergency or crash landing. However, a quick look at the crash photos tells a different story.
First, a line becoming entangled in the trees is not necessarily an emergency for an experienced and properly trained long line pilot, which I have no doubt this pilot was. A helicopter pilot performing long line operations in and around trees or other obstacles will be leaning out the door far enough to keep an constant eye on the line and load. That is why it is also referred to as "vertical reference flying" because the pilot is often looking straight down at the ground and his load, and flying the helicopter by visual reference to the ground below him instead of out in front of him or her.
This type of flying is generally slow, with an emphasis on precision. If a line becomes entangled the pilot simply works to get the line untangled, or "pickles" (releases) the load. These hooks on the belly of the helicopter generally have an electronic release button, with a back up manual release handle both mounted right on the cyclic. Pilots are also trained to test both release methods prior to any long line work.
The greater danger in performing long line work is that you are often working outside of the height velocity curve that is publised in the operating manual for every helicopter. This is also sometimes called "dead mans curve."
In the event of an engine out the helicopter absolutely must have an acceptable combination of altitude and airspeed in order to enter autorotation. The right combination of altitude and airspeed will keep the air rushing up through those rotor blades (collective must be immediately lowered) and keep them turning at a sufficient rpm and with enough energy to cushion the landing. This technique works every time when performed properly and when operating inside the published height velocity diagram, (500' and 60 knots is an example of a good altitude and airspeed combination for most helicopters, while 200' and 20 knots or a hover at 200' is an example of a height and velocity where most helicopters would be incapable of performing a successful autorotation.)
However, long line operations by their nature require pilots to operate outside of the height velocity diagram. If you are using a 100' line and you are in a precision hover picking up or placing a load then you are operating outside of the height velocity diagram. This is perfectly legal, and helicopter pilots accept this risk when performing long line operations as well as certain other helicopter maneuvers.
While I am not a trained helicopter accident investigator certain logical conclusions can be drawn simply by examining the photos published in the news stories of this crash. All 5 blades on this helicopter are completely intact and do not appear to have any damage normally associated with blades which are spinning at flight rpm, and involved in a crash. One would expect to see splintered blades, deeply gouged dirt and much more significant damage to the cabin fuselage if the crash occurred with the engine and rotorblades spinning at the proper rpm. Instead you see blades that are intact but drooped and touching the ground on all sides of the aircraft, much more indicative of a very hard impact with low rotor rpm.
Rather than getting his line caught in the trees as reported by a number of news outlets, this helicopter more likely experienced engine problems or an engine out while flying outside of the height velocity curve. Even the best helicopter pilots in the world may not have been able to recover and survive such an occurance.
This is tragic and sad event for helicopter aviation and PHP.com sends it's condolences to the pilot's family and friends.
According to the FAA the helicopter was a Hughes 369D manufactured in 2002 and owned by Utility Helicopters Inc at 1948 Joe Crosson Dr in El Cajon Ca., (Gillespie Field).
The helicopter was likely leased or contracted out to Geokinetics of Oregon for the survey work being conducted.
The NTSB has released it's preliminary investigation report on this incident. The report does make clear that damage to the helicopter is consistent with a "high vertical descent rate." This preliminary report also confirms that the long line and the load were located in trees, 281 feet from the helicopter, indicating that the pilot indeed released the load likely when other trouble developed. All the evidence is still consistent with an "engine out" while outside the height velocity curve.
As I noted in the initial post above, virtually all of the news media at the time of the crash reported that the helicopters load became entangled in the trees, inferring that this lead to the crash. This report gives no indication that the load became entangled in trees, or that entanglement was in any way a factor.