Tuesday, March 26, 2013
Integrated Safety Systems Keep Helicopters Out of the Evening News
The following is submitted commentary from Honeywell Aerospace, written by Mike Madsen, president of Defense & Space. It does not constitute an endorsement from Rotor & Wing.
While any helicopter accident is one too many, it’s hard not to feel a visceral reaction when you hear of an EMS team going down while attempting to save the lives of others.
In November 2011, the Interior Minister of Mexico, Francisco Blake Mora, lost his life along with seven others in a rotorcraft accident. Credited with making major strides in the government’s war on drug cartels, Blake Mora was at first presumed to be a victim of sabotage. However, investigators have since determined that foggy conditions had disoriented the pilot, who had no sensor system on board to warn him of unseen terrain obstacles.
Prior to that, in September 2008, a pilot and medical crew died after evacuating two injured teenagers from an automobile accident in Maryland. The reported cause: pilot disorientation resulting from an unexpected weather system that could have been avoided had the pilot been alerted to it. Another mishap in June 2006 killed Los Angeles Fire Department personnel as well as the child they’d rescued from a freeway collision. Investigators concluded that this resulted from catastrophic failure of the helicopter’s tail rotor that an onboard monitoring system could likely have predicted.
Such tragedies typically end in complex, costly litigation that drags on for years—and also tarnishes the public’s perception of rotary wing aircraft as a reliable platform for emergency response and other societal needs. We can avoid perpetuating the blame game—and increase the public’s confidence in helicopter travel—by pursuing and implementing technological approaches that mitigate hazards before they make the evening news.
Improving the Comfort Level for Public and Pilot
Governments and enterprises around the world are finding new uses for rotorcraft every day, which makes for a bright industry outlook. At the same time, it creates an urgent business case for increasing the public’s comfort level with the helicopter, both as a trustworthy conveyance and as an increasing factor in daily air traffic.
Honeywell SVS approaching New York City. Photos courtesy of Honeywell
Viewing these concerns from a business-case perspective, it’s tough to ignore the convergence of three factors:
• Civil rotorcraft sales are projected to ramp up globally over the next five years as new roles and regions are opened up to the helicopter’s unique capabilities.
• Increasing airspace congestion and rapidly changing man-made airspace obstacles place an ever-heavier workload on the helicopter pilot, who arguably has a more demanding job than fixed-wing aircrews to begin with.
• This upsurge in rotorcraft and their roles—particularly in airspaces unaccustomed to them—puts a larger percentage of less experienced pilots in the air, creating an even greater need for helicopter safety systems.
“If you look to the future and don’t like what you see, change it.” At Honeywell, we’ve been answering that call since the 1960s, when we first fielded a Ground Proximity Warning System (GPWS) for fixed-wing aircraft. Two years ago, the FAA first approved our Enhanced GPWS (EGPWS) for rotorcraft, which has evolved in critical ways to improve situational awareness, reduce pilot workload and overcome low¬¬-visibility disorientation. We’ve also fielded health and usage monitoring systems (HUMS) that use onboard vibration diagnostics and proprietary algorithms to detect mechanical faults before they result in catastrophic failures.
EGPWS: What It Can Do Now
Developed by a team of engineers led by Donald Bateman, chief engineer of flight safety systems for Sundstrand Data Control (now Honeywell), GPWS technology consisted mostly of a vertical downward look provided by a radar altimeter. It saved many lives but gave at best a 30-second advance warning of terrain rising up to meet the aircraft—which was certainly preferable to no warning.
The great leap forward from GPWS to Enhanced GPWS followed the advent of global positioning system (GPS) technology in the late 1980s. GPS gave aircrews a much more accurate reading of their location on the earth’s surface in terms of latitude and longitude. They now had a much clearer picture of where they were relative to terrain features.
We also developed a set of proprietary algorithms that provided a predictive “look-ahead” capability. Even if a pilot entered into a banked turn, for example, the EGPWS could now anticipate that trajectory and warn against obstacles in the corresponding sector. Instead of a 30-second warning of hazards directly below the aircraft, aircrews could now have several minutes of advance notice based on their actual direction of travel.
However, this technological leap raised another question: If we can now pinpoint an aircraft’s location with great accuracy relative to terrain that could affect its well-being, can’t we also make sure the terrain maps are as accurate, complete and up-to-date as possible?
So, rather than rely on maps produced over the past century by various government agencies or international consortiums, Honeywell undertook its own multi-year, multi-million-dollar digital terrain-mapping project. Because man-made terrain features change so often—consider the burgeoning wind-farm industry, for example—we view this global map as a perpetual work in progress. EGPWS customers can access and update these maps at frequent intervals.
Helicopters Have Special Needs
Driven by an upward trend in controlled flight into terrain (CFIT) incidents, the FAA and Europe’s EASA mandated EGPWS for most fixed-wing commercially operated aircraft in the mid-90s. This all but eliminated CFIT in the air transport industry. But the abrupt turnaround served to highlight an even steeper increase in the incidence of rotary wing CFIT accidents, most of them associated with the rise in emergency response (medevac, search and rescue, law enforcement, firefighting) as well as the general increase in rotorcraft usage across the board.
Because of their unique flight regimes, developing an effective, reliable EGPWS for rotary-wing platforms would prove to be a taller order. Not only do they hover and drop vertically into confined spaces, they can fly laterally and backward. In addition, they typically have severe payload and power-supply limitations that restrict the quantity and power consumption of add-on components.
With their remarkable versatility, helicopters fly into secluded, often unimproved sites that don’t offer instrument landing systems or other infrastructure common to commercial airports. This can create a very taxing environment for the pilot.
More to Safety Than Just Technology
While Honeywell is committed to staying out in front technologically, we’ve also put significant emphasis on humanizing the EGPWS. The term “user-friendly” has become a cliché these days, but we’ve simplified and automated the EGPWS processes so that a pilot can turn on the device and get what he needs from it with minimal training and effort, even if he flies mostly in bright daylight conditions. We continue to move tasks off the pilot’s plate and onto the machine’s, providing only the need-to-know information.
When we brought the rotorcraft edition of EGPWS to market, we didn’t just stop there. We’ve continually evolved it, adding a tail-strike warning and an autorotation mode that assists the pilot in achieving a safe glide slope and touchdown in case of engine failure. We’ve also made it easier to integrate with other safety systems, such as weather radar and traffic collision avoidance systems (TCAS), and consolidate them onto a single display. Above all, we’ve gone to great lengths to make EGPWS trustworthy. If a pilot ever gets a false alarm, or doesn’t receive an alert when he should have, our 24/7 tech support team wants to know about it and fix it.
Although the EGPWS may be a technological marvel, it also requires a current terrain database and the means to keep it updated. That’s why we developed and continue to update our own global database in order to ensure we have the best information possible.
HUMS: Monitoring Bad Vibes to Saves Lives, Cut Costs
While a 1990s survey of rotorcraft accidents attributed roughly one-third of them to CFIT induced by spatial disorientation and one¬¬-third to CFIT stemming from pilot judgment errors, it traced the remaining third to mechanical failures. This led to the development of onboard health and usage monitoring systems (HUMS) that could prevent catastrophic failure by detecting mechanical faults early on.
It was a UK fleet operator servicing offshore oil rigs in the North Sea that first voiced an urgent demand for an onboard monitoring system. In this unforgiving environment, the fleet’s ability to guarantee operational availability of its aircraft on a daily basis was the make-or-break factor in its success. Now in their fifth generation of development, HUMS have evolved into more affordable and highly capable assets that reduce operating costs as they save lives.
Using an array of accelerometers and other sensors housed in one compact box, Honeywell’s Zing HUMS monitors vibration of all critical rotating parts continuously during flight, requiring no human intervention. The Zing acquisition unit collects, processes and interprets data from the engines, gearbox, shaft, fans, rotor system and other drive-train components. At flight’s end, it generates a clear, concise report of actionable diagnostic and prognostic information.
The proprietary algorithms we’ve developed for Zing HUMS identify specific maintenance procedures before they become evident, helping fleet operators avoid unplanned downtime or expensive repairs at remote locations. They can now practice condition-based maintenance, which is much less costly than an interval-based or run-to-failure approach. Now that they don’t have to allow for unplanned downtime, fleets can provide the same number of flight-hours per month with fewer aircraft.
Embracing Helicopter Safety: Government-Driven vs. Customer-Driven
The FAA, with endorsement of the National Transportation Safety Board (NTSB), issued a Technical Standard Order (TSO) in 2009 specifying minimum requirements for what it calls a terrain awareness and warning system, or TAWS (known as EGPWS to the industry). The agency is currently adding a mandate to its Federal Aviation Regulations (FAR) requiring commercially operated helicopters to carry a TAWS. Honeywell, along with other EGPWS suppliers, submitted its comments on the draft regulation in January 2011.
However, it’s worth noting that commercial operators have taken the initiative on their own to install some 4,000 such systems on their equipment as retrofits. In addition, major rotorcraft manufacturers Bell, Eurocopter, Sikorsky and AgustaWestland have begun offering an EGPWS as optional equipment on their leading models.
While the sense of urgency surrounding mechanical failure has not quite caught up with the concern over CFIT, the demand for HUMS among fleet operators has increased dramatically in the past five years. In these times of austere operating budgets and high fuel costs, they see it more as a business-saving than as a lifesaving adjunct. In response, Eurocopter and Sikorsky have begun offering Honeywell’s Zing HUMS as an option, and it appears likely that HUMS will become standard equipment before 2020 rolls around—with or without government mandate.