Memphis, TN, USA
N802HK
EMBRAER EMB145 - EP
After receiving intermittent localizer indications on the airplane’s first approach to the airport, the flight crew, conducted a go-around, and air traffic control cleared the flight for a second approach. The captain indicated that, while the airplane was level at about 2,000 ft on the base leg, the flight entered clouds. The first officer stated that she noted moisture on the windshield wiper and the captain indicated that the wind screen was wet. The cockpit voice recorder (CVR) recorded the captain and first officer briefly discussing ice; however, the airplane’s ice protection system, which was set to the automatic mode, did not operate automatically, and the crew did not activate the system manually. The crew did not see the ice light come on and there were no icing messages on the engine indicating and crew alerting system. As the first officer was applying control inputs to adjust for a crosswind, a rapid roll to the right occurred, which resulted in a wing strike and substantial damage to the airplane. About forty minutes after arrival at the gate, an examination of the airplane found an accretion of ice on the leading edge of both wings. The aircraft performance study, which correlated icing charts with the airplane’s flight profile, determined that the airplane spent over 20 minutes at altitudes where icing was probable during both approaches. The study concluded that the right roll was not commanded by the flight crew but likely due to ice buildup. Although the vertical load factor did not indicate that the airplane experienced a full aerodynamic stall, the ice buildup likely created enough flow separation on one wing for it to lose lift during the flare, without affecting the control of the aircraft in a measurable way during the approach. After the accident, the ice detection and anti-ice systems were tested at the aircraft level with no anomalies identified. The ice detectors were also functionally tested by the manufacturer at the component level with no anomalies identified that could have contributed to the event. A review of FDR data revealed that no failures were recorded for the ice detection system during the accident flight. Additionally, the system operated as expected during a manual preflight test and detected icing conditions during the previous flight. A review of the maintenance records did not reveal any systematic problems with the ice detection system. Therefore, it could not be determined why the ice detection system did not detect the presence of icing conditions even though the airplane accreted ice during the approach. This possibly could have been due to variations in static air temperature that prevented the ice that accumulated on the sensors from reaching the alert threshold or the occurrence of meteorological conditions out of the 14 Code of Federal Regulations Part 25 Appendix C during approach, or a combination of these two factors.” Although the ice detection system did not automatically activate the ice protection system, the CVR recorded a brief discussion during the final approach indicating that the crew was aware that the airplane was picking up “a little bit” of ice. According to the Trans States Airlines EMB145 Airplane Operations Manual (AOM) and Standard Operating Procedures (SOP), even though the airplane is equipped with an ice detector, the crew was responsible for monitoring icing conditions and for manual activation of the ice protection system when necessary. Therefore, the crew recognized that the airplane was operating in icing conditions and accumulating ice and should have manually activated the ice protection system. It is likely the crew's overreliance on automation for the activation and proper operation of the ice and rain protection system resulted in their failure to adequately monitor the system and respond appropriately when it did not activate automatically. Although the AOM and SOPs indicated that the crew is responsible for monitoring icing conditions and for manual activation of the ice protection system when necessary, there was no information in Trans States Airlines ground training modules that presented the crew as being responsible for monitoring and activating the ice and rain protection system when no warnings or cautions were received from the EICAS. Additionally, manual ice detection methods for flight crews to use when flying in potential icing conditions were not specifically referenced during ground training. The Trans States Airlines manager of flight standards said that manual selection of the anti-ice system was not emphasized in training like the automatic mode of operation was during flight operations. It is possible that because the manual operation of the airplane's ice protection system was not emphasized during training, the crew may not have recognized the need to perform this task. Trans States Airlines issued an operations bulletin after the accident that stated interim procedures for crewmembers to follow when operating in potential in-flight icing conditions. The bulletin called for active monitoring of the deicing/anti-icing equipment and, if it did not activate, to accomplish the QRH's Ice Detectors Fail procedures.
HISTORY OF FLIGHTOn February 5, 2014, about 0015 central standard time, an Embraer 145EP (EMB-145), N802HK, operating as Trans States Airlines flight 3395, was landing on runway 36R at Memphis International Airport (MEM), Memphis, Tennessee, when it suddenly rolled to the right, and the right wing struck the runway. The 44 passengers and crew onboard were not injured, and the airplane sustained substantial damage. The flight was operating under the provisions of Title 14 Code of Federal Regulations Part 121 as a scheduled passenger flight from Houston International Airport (IAH), Houston, Texas, to MEM. Instrument meteorological conditions (IMC) prevailed at the time of the accident. The accident flight was the flight crew's first flight in the accident airplane that day. The first officer was the pilot flying and the captain was the pilot monitoring (PM). According to the flight crew, the preflight inspection was routine, and the anti-ice system was not tested because it was only required before the airplane’s first flight of the day. The crew indicated that the departure, climb and cruise phases of flight were uneventful. During the descent, the airplane entered a cloud layer about 3,500 ft mean sea level (msl). Air traffic control (ATC) then vectored the flight to a final approach for an instrument landing system (ILS) approach to runway 36L. According to the crew, before reaching the final approach fix (FAF), they received intermittent localizer course indications on both primary flight displays during the approach. Neither crewmember recalled observing any indications of icing during this approach, and the captain said he noticed no engine indicating and crew alerting system (EICAS) messages for ice. Inside the FAF, the crew stated the localizer course indications were intermittent again, and they elected to execute a missed approach. According to the aircraft performance study, at 2353, when the go-around was initiated, the airplane was at an altitude of about 2,000 ft. The airplane subsequently climbed to 3,000 ft during the go-around before it returned to and stayed at an altitude of 2,000 ft for about 12 minutes. The study indicated that during the go-around, the airplane spent an additional 19 minutes at an altitude with an increased probability of icing. The crew notified ATC of the localizer course difficulty they were experiencing on the approach, and the captain requested vectors to the ILS approach to runway 36C. That runway was not available, and ATC cleared the airplane for the ILS approach to 36R. The captain indicated in a postaccident interview that, while the airplane was level at 2,000 ft, on the base leg to runway 36R, the flight entered clouds. The first officer stated that, near the FAF for the ILS approach to runway 36R, she noticed moisture on the windshield wiper and observed something on the windshield; the captain stated that the wind screen was wet. About 0011, the cockpit voice recorder (CVR) recorded the first officer stating, “are we getting’ ice now,” and the captain replied, “a little bit.” The airplane's ice protection system was in the automatic mode and did not activate nor did the crew manually activate the system. The first officer indicated in a postaccident interview that they did not see the ice light come on and there were no icing messages on the EICAS. At the FAF, the localizer course signal was uninterrupted, and the airplane's autopilot captured the course. About 0012, the CVR recorded the crew discussing the airplane being configured with landing gear down and 45° of flaps; the captain indicated in a postaccident interview that it was on a stabilized approach at 1,000 and 500 ft. The crew continued the ILS approach, and near the approach minimums (about 400 ft above ground level [agl]), the airplane exited the clouds and the crew observed the landing runway. FDR data indicate that, during the final descent to the runway, the airplane's speed reduced to 130 kts. According to the captain, the first officer announced "landing" and disconnected the autopilot using the control yoke switch when the airplane was about 300 ft above the runway. After the autopilot was disconnected, the CVR recorded numerous “autopilot” audio messages in the cockpit. The first officer indicated in an interview that she attempted to turn off the audio message but was unable to do so. The CVR recorded the first officer asking, “Why is she not shutting up?” The captain stated that he then held the quick disconnect button for the autopilot to silence it. After the autopilot disengagement, the captain gave a speed warning to the first officer. He stated in an interview that the first officer "got a little slow" (between 5 to 6 kts) during this time and estimated the airplane to be about 100 to 150 ft agl but that the first officer called “correcting” and “got back on speed.” The first officer recalled being slow by about 4 kts. According to the crew, when the airplane was about 20-40 ft agl, as the first officer was applying control inputs to adjust for a crosswind, a rapid roll to the right occurred. According to the performance study, the airplane began to roll quickly to the right just before 0015, followed by stick shaker activation. One of the airplane's two angle of attack (AOA) sensors reached 15°, and the indicated airspeed was 113 kts; the airplane's maximum roll attitude, which coincided with the stick shaker activation, was 28° right wing down. The airplane's wing struck the runway, and the airplane landed hard on the right side of the runway. The CVR recording and postaccident crew statements indicated that the pilots believed that the sudden roll to the right was caused by a rudder hardover. However, FDR data did not show any evidence of a large rudder surface deflection. About 40 minutes after the airplane landed, taxied to, and arrived at the gate, the crew observed ice on the wings, horizontal stabilizer, and both engine inlets. The first officer indicated that the airplane was covered in ice, and the captain indicated observing “a lot of ice” on the leading edge of the wings. PERSONNEL INFORMATIONAll crewmembers were current and qualified in accordance with Federal Aviation Administration (FAA) regulations and Trans States Airlines requirements. The Captain The captain was hired by Trans States Airlines in August 2005. A review of the captain's FAA records did not reveal any prior accidents, incidents, or enforcement actions, and a review of his driving records showed no revocations or suspensions. He held an Airline Transport Pilot certificate and had accumulated 6,400 hours of total flight experience, of which about 5,600 was in the Embraer 145. The captain was based in St. Louis, Missouri, and was on the first day of a 5-day reserve period. The accident flight occurred on his fourth leg of the day. The captain did not recall what time he awoke on February 4 but stated that he had normal sleep and felt rested. He said he departed his home in St Louis about 1115 and checked in for duty about 1300 for a scheduled departure of 1345. On February 3, he was at his residence and did not recall what time he awoke but spent the day at home. He did not recall what time he went to bed but stated that he slept "well." On February 2, he had returned from vacation about 1100 and said he had normal sleep that night. The First Officer The first officer was hired by Trans States Airlines in September 2012. A review of FAA records did not reveal any prior accidents, incidents, or enforcement actions, and a review of her driving records showed no revocations or suspensions. She held an Airline Transport Pilot certificate and had accumulated 930 flight hours as second in command in the Embraer 145. The first officer was also based in St. Louis. The accident flight was her third leg of the day. She indicated that, on February 4, she awoke about 0900 and had slept "well" and that, on February 3, she awoke about 0530 and slept "well." She flew from MEM to Chicago, Chicago to Moline, and Moline to Chicago. She checked into the hotel for a 27-hour layover and went to bed about 2200. On February 2, she commuted in the night prior. She indicated that she awoke about 0400 and had slept well. She flew two flight legs. Her duty day ended at 1100, and she was in bed about 2000. AIRCRAFT INFORMATIONIce Detection System The ice detection system is used to detect and alert the crew about the formation of ice. It is the primary source to automatically activate the airplane’s anti-icing systems for the wings and engines. The ice detection system is comprised of two identical ice detection circuits that operate independently during all phases of flight. Each ice detection system circuit has the following components: ice detector, ice detector relay, ice protection overhead panel, circuit breakers, and data acquisition unit. The ice detector is a one-piece unit including the sensor and processing electronics that detect the presence of ice. When either of the ice detectors detect ice, an advisory message "ICE CONDITION" is shown on the EICAS display, a signal would be sent to the anti-ice system valves to activate them to open, and a signal would be sent to the full authority digital engine control to activate the automated engine icing thrust setting logic to limit the thrust to a minimum acceptable level. The icing signal stays active for 60 seconds. At the same time the icing signal is activated, the ice detector heaters are turned on to deice the detector strut and probe. When the sensing probe is deiced, it is ready to sense ice again. If the icing condition continues and the ice thickness switching level is reached before 60 seconds has passed, the icing signal is continuous. All anti-ice functions operate when one or both detectors detect ice. The ice detectors are self-monitored through built-in test circuits. A detected failure in either detector would cause a change to the status output signal. This would activate a caution message "ICE DET 1 FAIL" or "ICE DET 2 FAIL" on the EICAS display. The failed unit would not detect ice after an internal failure detection. If a dual ice detector failure condition was present, a caution message "ICE DETECTORS FAIL" would be shown on the EICAS display. If ice detector No. 1 failed, or if both detectors failed simultaneously, the "Ice Detection Fail" parameter on the FDR would also switch to the failed state. A rotary switch on the ice protection overhead panel allows for a manual test of the ice detectors. Moving the test switch left or right would test the corresponding ice detection system. During the test, the advisory message "ICE CONDITION" is shown on the EICAS display and the caution message "ICE DET 1 FAIL" or "ICE DET 2 FAIL" was shown on the EICAS display. During a manual test of the No. 1 ice detection system, the status of the ice condition output and ice detector fail output would be recorded on the FDR. These parameters would not be recorded on the FDR during a manual test of the No. 2 ice detection system. The ice detection system would provide the following ice detection messages on the EICAS display: ICE CONDITION Status: ADVISORY. Condition: During ice detector ground test or in-flight detected icing condition NO ICE-A/ICE ON Status: CAUTION. Condition: Any bleed air valve is activated when no icing condition is detected. This message is inhibited on the ground. This message will occur if the ice detection override switch is not in the "AUTO" position and ice is not detected during flight. ICE DET 1 (2) FAIL Status: CAUTION. Condition: Failure of any single ice detector ICE DETECTORS FAIL Status: CAUTION. Condition: Failure of both ice detectors. Trans States Airlines EMB145 Airplane Operations Manual (AOM), Volume 2, section 2-15, indicated the following: Ice detectors 1 and 2 are respectively installed at the airplane's left and right nose section, to provide icing condition detection. The ice detector was designed to pick up ice quickly. Therefore, in most cases, ice would be detected before it would be noticed by the crew. NOTE: Notwithstanding ice detector monitoring, the crew remains responsible for monitoring icing conditions and for manual activation of the ice protection system if icing conditions are present and the ice detection system is not activating the ice protection system. Ice and Rain Protection System According to the Trans States Airlines EMB145 AOM, Volume 2, Ice and Rain Protection, the airplane's ice protection system heats critical ice accumulation areas through use of either hot bleed air or electrical power. The system is fully automatic and, under icing conditions, activates the entire anti-ice system, except for the windshield heating system. Adequate ice protection for the wings and horizontal stabilizer leading edges and engine inlet lips is obtained by heating these surfaces with bleed air from the engines. The electrically heated areas are the windshields (must be manually activated), pitot-static tube, AOA sensors, true air temperature (TAT) probes, analog to digital computers, pressurization static ports, lavatory water drains and water service drains. The ice and rain protection system provides signals to the EICAS that displayed appropriate system malfunctions. In the automatic mode, the system is turned on through activation of the ice detector. The crew could manually activate the system through the OVERRIDE knob on the ice detection panel. Setting the OVERRIDE knob to the ALL position activates the system. Ice Protection Control Panel The ice protection control panel was located on the rear corner of the cockpit overhead instrument panel. Trans States Airlines EMB145 AOM, Volume 2, Ice and Rain Protection, pages, 18-20, depicted the switches and indicators available to the flight crew: engine air inlet anti-icing buttons, wing anti-icing button, horizontal stabilizer anti-icing button, sensor heating buttons, windshield heating button, ice detection test knob, and ice detection override knob. Wing Inspection Lights The Trans States Airlines EMB145 AOM, Volume 2, External Lighting, page 2, described the wing inspection lights: Two inspection lights, one on each side of the fuselage, provide lighting of the wing leading edge to allow the crew to verify ice formation. The inspection lights are controlled by a switch located on the overhead panel. A Trans States Airlines EMB-145 aircrew program designee (APD) stated in an interview that it was hard to see the EMB-145 wings from the cockpit in all conditions. A Trans States Airlines EMB-145 check airman made a similar observation. An evaluation of an exemplar EMB-145 airplane during hours of darkness revealed that only about the last 3 ft of the leading edge of the wing could be observed from the cockpit from each respective side. METEOROLOGICAL INFORMATIONThe MEM weather before the accident reported by the automatic terminal information service at 2354 was wind from 280° at 10 kts, tower visibility 1/2 mile, ceiling overcast at 400 ft agl, temperature 1°C, dew point temperature -1°C, and an altimeter setting of 29.95 inHg. Surface visibility was 8 miles, and the 3-hour precipitation was 0.10 inch. The METAR provided after the accident at 0054 was wind from 290° at 12 gusting to 19 kts, tower visibility 1/2 mile in mist, ceiling overcast at 400 ft agl, temperature 1°C, dew point temperature -1°C, and an altimeter setting of 29.99 inHg. At the time of dispatch, there were no National Weather Service advisories for icing conditions over the route of flight. Icing charts from the National Center for Atmospheric Research for 0000 in the region of MEM indicated a probability between 50 to 70% of trace to light icing conditions between 1,000 and 2,000 ft agl. The charts for 0100 depicted light icing conditions below 3,000 ft agl with the probability increasing to 85%. AIRPORT INFORMATIONIce Detection System The ice detection system is used to detect and alert the crew about the formation of ice. It is the primary source to automatically activate the airplane’s anti-icing systems for the wings and engines. The ice detection system is comprised of two identical ice detection
the failure of the flight crew to adequately monitor the system for proper operation and manually activate the system during the flight in icing conditions. Contributing to the accident was the crew's limited training on the manual operation of the anti-ice system and the nonactivation of the automatic ice detection system for reasons that could not be determined.
Source: NTSB Aviation Accident Database
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