Unprepared For The Ice

The NTSB's probable cause for the accident was adopted this past June. It was shockingly straightforward: "...the pilot's conduct of an approach in structural icing conditions without turning on the airplane's wing and horizontal stabilizer deice system, leading to ice accumulation on those surfaces, and without using the appropriate landing performance speeds for the weather conditions and airplane weight, as indicated in the airplane's standard operating procedures, which together resulted in an aerodynamic stall at an altitude at which a recovery was not possible."

Although the NTSB did its usual workman-like job of establishing the facts and scenario for a high-profile accident like this, it was unable to conclude why the pilot made his fatal mistake.

The T-tail EMB-500 Phenom 100 was Embraer's first entry into the growing field of entry-level single-pilot light jets. The Brazilian manufacturer received the EMB-500 type certificate as year 2008 was coming to a close. The accident airplane was one of 97 Phenom 100s built in 2009. Two Pratt & Whitney Canada PW617F-E turbofan engines provided the power. A popular configuration had four passengers occupying club seating in the back, with a fifth passenger in the right front seat during single-pilot operations. The airplane also can be configured to hold up to seven passengers. It can cruise at 390 knots and reach FL410.

The accident pilot had logged about 4,600 hours when he began transitioning to the Phenom in March 2014, and had logged about 136 hours in the airplane at the time of the accident. The instructor at the company that provided his initial Phenom training characterized him as very intelligent, highly motivated and great at memorization. But, when it came to piloting, the instructor said his progress was slow because he sometimes became task-saturated, and fixated on one small task at the expense of a critical task. He said the pilot originally asked for just an abbreviated training course, and had to be talked into taking a full course. The pilot passed his checkride for the type rating after about 46 hours of instruction, and took recurrent training with the checkride examiner about three months before the accident. At the time of the accident, the pilot was ATP-rated for single-engine and multi-engine land, was a flight instructor for single-engine land, held the Phenom type rating, and had a current second-class FAA medical. According to a report by the FAA's Flight Standardization Board, the norm for obtaining an EMB-500 type rating for pilots in Part 135 operations is 12 hours training. A commercial training school advertises that its EMB-500 type-rating courses take two or three days.

The airplane was equipped with a cockpit voice and data recorder (CVDR). It fired up when battery power came alive at about 9:39 a.m., on the morning of the accident, and indicated that the first engine was running within a minute. Investigators suggested that the pilot short-circuited at least some of the checklists, because the data showed that by 9:45 the airplane was accelerating for takeoff. It took investigators nine minutes to complete the five checklists that were supposed to be accomplished before takeoff when they timed themselves in another Phenom 100. There was no evidence on the CVDR of an automated voice announcing "takeoff okay," which should have been heard in response to the pilot pressing the "takeoff configuration" button if the airplane was properly configured for takeoff. The announcement confirms that the flaps and trim are set for takeoff and the parking brake is released.

By 9:47, the autopilot had been turned on. Thirteen minutes later, the passenger in the right front seat commented, "...looks like we're in the clouds." The pilot said, "Yeah," and within a few seconds the engine anti-ice and wing and stabilizer deice were turned on. Two minutes later, when the airplane was at FL230, deice and anti-ice were turned off. There were 241 miles between KIGX and KGAI, and the cruise portion of the flight was uneventful. At about 10:09, the voice recorder picked up the AWOS from KGAI reporting the wind from 070 degrees at 2 knots, visibility greater than 10 miles, few clouds at 2,300 feet AGL, overcast ceiling at 2,800 feet, temperature minus 1 degree C and dewpoint minus 9 degrees C. Investigators noted that the Airplane Flight Manual required the ice-protection systems to be turned on during a descent in weather like what was being reported at Gaithersburg.

The airplane began its descent from FL230 at about 10:12. At about 10:19, Washington Center handed off the flight to Potomac Terminal Radar Approach Control (TRACON). KGAI is an uncontrolled field. The flight was cleared down to 5,000 feet and handed off to another TRACON controller. The pilot advised that he had the weather and asked for the GPS approach to Runway 14. During the descent, the airplane encountered a temperature inversion in which the total air temperature (TAT) went as high as 12 degrees C, according to data on the CVDR. TAT is warmer than the actual air temperature because of the effects of airspeed. As the descent continued, TAT was about 5 degrees C, at 5,000 feet MSL. TAT was shown to the pilot on the primary flight display (PFD).

At about 10:31:11, the pilot commented, "...ground, I see the ground." The right seat passenger replied, "Yep." Five seconds later, the controller radioed the pilot to cross a fix that was 11 nautical miles ahead at 3,000 feet and cleared him for the approach. The pilot made a mistake in his readback, saying "one three thousand" instead of three thousand. The controller didn't correct the mistake.

At 10:35:13, the pilot called in the blind on the Gaithersburg Common Traffic Advisory Frequency (CTAF) that the flight was "...ten out, we're just starting GPS one four approach." The pilot of an airplane at the airport asked, "...hey, aircraft on GPS, any precip out there?" The Phenom pilot asked for the question to be repeated, and the reply was, "...ah, yeah, just, ah, seein' if you got...we're on the ground here...seein' if you're getting any precip out there."

Just then, the controller asked the pilot to advise cancellation of IFR either on the approach frequency or on the ground, but the CVDR indicated that the controller was blocked from the pilot's headset because he was transmitting to the pilot on the ground, "...ah, we're kind of in and out of the clouds here...and that's at three thousand." In the next minute, there was additional radio traffic on the CTAF, which the CVDR indicated was being heard by the pilot. The recorder picked up changes in engine sounds, indicating power increases and decreases. At 10:38:20, the controller asked if the pilot was still on frequency, to which he replied, "...sure are." The controller asked, "What was your response to canceling?" The pilot said, "Ah, we're IMC at the moment, but we should be, ah, we should be clear in a minute or two. We'll let you know." The controller approved a change to the CTAF, and told the pilot to keep the current transponder squawk and not to forget to cancel IFR. At the same time, the CVDR picked up the sound of an altitude alert chime and an automated voice saying, "altitude."

At about 10:39:10, the pilot radioed they were seven miles from the airport, straight-in for Runway 14. Then, the pilot said to his right-seat passenger, "...so your job is to find the airport." The passenger laughed and said, "Uh, huh." The pilot said, "...just look straight ahead and say ’airport in sight.'"

Another pilot on frequency warned, "...watch out for birds in the vicinity of one four." The Phenom pilot said, "Okay, thanks." The pilot then engaged in banter with another pilot on the frequency. At about 10:40:03, the right-seat passenger said, "Snow," just as the pilot announced on the radio that they were now six miles out. The pilot exclaimed, "Wow, there's snow," and engaged in more small talk with that other pilot on frequency. There's no evidence that the pilot realized the airplane was picking up ice.

At 10:40:34, the passenger said he thought he saw the airport, followed by, "Oh, I see it, I see it, yep." The pilot said, "There it is...straight ahead."

The CVDR recorded numerous clicks and changes in engine sounds indicating that the power was being reduced to help slow the airplane while the pilot was asking on the radio if another airplane was going to remain in the traffic pattern. Beginning at about 10:41:35, there were 15 automated stall warning announcements heard on the CVDR along with clunking noises and increased engine noise. The pilot repeatedly said, "Whoa," and the passenger said "Oh, no." The sound of impact was at about 10:41:55.

Although the airplane had a stick pusher system to force the control column forward to prevent a stall, there's no indication it activated. With gear and flaps down and ice protection off, the stall warning and stick pusher will wait for a slower speed to activate than when the wing and horizontal stabilizer deice are turned on. The investigation determined that if ice protection was on, the stall warning would have gone off about 20 seconds earlier, when the airplane was at 1,000 feet above the ground and 10 knots faster. If there had been an early attempt at stall recovery and altitude loss during recovery was kept to the Phenom's claimed 300 to 500 feet, the accident likely would have been avoided.

Investigators determined that before beginning the descent, the pilot had set a landing reference speed (Vref) of 92 knots, a speed based on performance data with anti-ice and deice being turned off. The data showed the airplane would stop with about 1,700 feet of the 4,202-feet-long runway remaining. However, the Vref when anti-ice and deice are turned on is higher: 121 knots, resulting in a calculated landing distance of 4,117 feet. Add 5 knots for icing conditions, and you have a minimum approach speed of 126 knots, leaving no breathing room at all at Gaithersburg.

The investigation determined that, with ice protection off, the top of the red band shown to the pilot on the PFD airspeed tape would place stall warning activation at 87 knots, the yellow 3 knots warning before red at 90 knots and the green circle indication of 1.3 times the speed at which the stick pusher would activate at 102 knots. In simulation, they found that with deice and anti-ice on, the airspeed tape showed red at 102 knots, yellow at 105 knots and green circle at 121 knots.

The NTSB explored three possible reasons for the pilot not using ice protection: He forgot to turn it on; he had it off to keep the required landing distance as short as possible; and he didn't understand the effects of icing on the airplane's performance. I have a fourth possibility.

The CVDR provides evidence that the pilot was busy and also distracted by radio traffic on the CTAF. He clearly wasn't practicing the sterile cockpit procedure, which calls for nothing but flight-essential communications while on arrival. The question remains: Was the pilot too task-saturated to turn on ice protection? He had no trouble multitasking in everyday business life. He clearly was aware of what ice protection is all about, having used the systems earlier in the flight.

Is it possible he didn't fully appreciate how ice affects performance of a jet? I doubt it. This pilot was intelligent, and he built his life and career on the application of science and data. Calculating performance numbers on the electronic devices he used in flight planning and management would have been second nature.

Did the pilot deliberately not use ice protection to keep the required approach speed as low as possible and the landing distance as short as possible? If his concern was with runway length, there's a simple and safe answer: different airport, longer runway. Perhaps he was worried because of an accident he had on a flight from KIGX to KGAI on March 1, 2010. His turboprop Socata TBM 700 touched down on Runway 32 at KGAI, with the stall warning horn sounding, and started to drift left. The pilot couldn't correct. He initiated a go-around. As the airplane lifted off, it banked left. The pilot applied full right aileron, but the airplane crashed. It's also possible that he heard about a recent EMB-500 Phenom 100 accident at Houston-Sugar Land Regional Airport (KSGR) in Texas. On November 21, 2014, the jet ran off the end of Runway 35 at KSGR when the brakes didn't work.

My fourth possibility? Perhaps the pilot believed the temperature inversion provided enough ice protection. His scientific mind might have calculated that they'd be out of the clouds before the temperature hit freezing again, so no need for ice protection and the extended landing distance. That mindset might help explain his surprise when the passenger told him it was snowing.

The Gaithersburg accident prompted the NTSB to suggest that the FAA and General Aviation Manufacturers Association develop equipment that automatically alerts jet pilots when they need to turn on ice-protection systems. It also recommended that the National Business Aviation Association work with its members to develop new training materials on winter weather, ice-protection systems and use of checklists. NBAA already has formed a special committee on single-pilot operations, which has released a video, "Alone in the Cockpit." It shows how easily an experienced pilot flying alone can be overwhelmed in challenging weather and traffic situations. I've watched it and recommend it. It's on the NBAA website and also on YouTube at youtu.be/xpa_VAGvC9U. You don't have to be a brilliant businessperson or scientific genius to realize that we all still have a lot to learn about flight safety and our vulnerabilities when single-pilot.

Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, visit www.ntsbreporter.us or write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.