Jacksonville, FL, USA
N732MA
Boeing 737
According to both pilots, the takeoff, climb, and cruise portions of the flight were uneventful. The No. 1 (left) thrust reverser was not operational and deferred for the flight in accordance with the airplane’s minimum equipment list. The captain was the pilot flying for the accident flight, and the first officer was the pilot monitoring. The captain was also performing check airman duties for the first officer who was in the process of completing operating experience training. During the approach to Jacksonville Naval Air Station (NIP), the flight crew had two runway change discussions with air traffic controllers due to reported weather conditions (moderate to heavy precipitation) near the field; the pilots ultimately executed the area navigation GPS approach to runway 10, which was ungrooved and had a displaced threshold 997 ft from the threshold, leaving an available landing distance of 8,006 ft. As the airplane descended through 1,390 ft mean sea level (msl), the pilots configured it for landing with the flaps set at 30º and the landing gear extended; however, the speedbrake handle was not placed in the armed position as specified in the Landing checklist. At an altitude of about 1,100 ft msl and 2.8 nm from the runway, the airplane was slightly above the glidepath, and its airspeed was on target. Over the next minute, the indicated airspeed increased to 170 knots (17 knots above the target approach speed), and groundspeed reached 180 knots, including an estimated 7-knot tailwind. At an altitude of about 680 ft msl and 1.6 nm from the threshold, the airplane deviated further above the 3° glidepath such that the precision approach path indicator (PAPI) lights would have appeared to the flight crew as four white lights and would retain that appearance throughout the rest of the approach. Eight seconds before touchdown, multiple enhanced ground proximity warning system alerts announced “sink rate” as the airplane’s descent rate peaked at 1,580 fpm. The airplane crossed the displaced threshold 120 ft above the runway (the PAPI glidepath crosses the displaced threshold about 54 ft above the runway) and 17 knots above the target approach speed, with a groundspeed of 180 knots and a rate of descent about 1,450 ft per minute (fpm). The airplane touched down about 1,580 ft beyond the displaced threshold, which was 80 ft beyond the designated touchdown zone as specified in the operator’s standard operating procedures (SOP). After touchdown, the captain deployed the No. 2 engine thrust reverser and began braking; he later reported, however, that he did not feel the aircraft decelerate and increased the brake pressure. The speedbrakes deployed about 4 seconds after touchdown, most likely triggered by the movement of the right throttle into the idle reverse thrust detent after main gear tire spin-up. The automatic deployment of the speedbrakes was likely delayed by about 3 seconds compared to the automatic deployment that could have been obtained by arming the speedbrakes before landing. The airplane crossed the end of the runway about 55 ft right of the centerline and impacted a seawall 90 ft to the right of the centerline, 9,170 ft beyond the displaced threshold, and 1,164 ft beyond the departure end of runway 10. After the airplane came to rest in St. Johns River, the flight crew began an emergency evacuation. The tailwind, the airplane’s excessive approach speed, and delayed speedbrake deployment increased the energy with which the airplane departed the runway and impacted the seawall, which contributed to the severity of the accident. However, postaccident landing performance calculations revealed that even if the airplane had landed on target speed within the operator’s specified touchdown zone, it would not have been able to stop before reaching the end of the paved runway surface due to the presence of standing water (with depths close to that defined as a flooded condition) on portions of the runway and the resulting viscous hydroplaning. Viscous hydroplaning is associated with the buildup of water pressure under the tire due to viscosity in a thin film of water between a portion of the tire footprint and the runway surface. The maximum wheel braking friction coefficient developed by the airplane during the landing ground roll was significantly less than the maximum wheel braking friction coefficient underlying the wet runway landing distances published in the airplane manufacturer’s flight crew operating manual (FCOM), computed by the operator’s onboard performance tool (OPT) application, and described in standards and models concerning landing performance in wet runway conditions. Conversely, had the airplane achieved the good braking action associated with a wet (but not flooded) runway published in the FCOM, it would have stopped on the runway even with the approach speed recorded before the accident landing, a 10-knot tailwind, and delayed speedbrake deployment. The operator’s guidance did not require flight crews to conduct en route landing performance calculations (landing distance assessment) under certain conditions, including reported braking action that is good or better, the use of maximum manual braking, and a tailwind of 5 knots or less. However, none of these criteria applied to the accident flight’s approach to NIP. No braking action reports were provided to or requested by the accident flight crew, the flight crew briefed using autobrakes rather than maximum manual braking, and the last wind report provided to the flight crew (240° heading at 10 knots) suggested that an estimated 7-knot tailwind component existed during the landing on runway 10. These considerations should have prompted the flight crew to perform updated landing performance calculations. However, had they done so, they still would have likely determined that the landing distance available on runway 10 was sufficient, under the conditions at the time, if they assumed good braking action (in the absence of reports indicating otherwise) and a merely wet (rather than flooded) runway condition. To address braking friction shortfalls observed during landings on wet runways, Safety Alert for Operators (SAFO) 15009 (current at the time of the accident) suggested that operators take appropriate action to address landing performance on wet runways such as “assuming a braking action of medium or fair when computing time-of-arrival landing performance or increasing the factor applied to the wet runway time-of-arrival landing performance data.” However, similar guidance was not included in the operator’s SOPs at the time of the accident. Had such guidance been included, the flight crew would have been obligated to assign a surface condition value indicating a condition worse than “good” because the runway was wet, which would have prohibited them from attempting the landing with the tailwind. To further clarify that advisory data for wet runway landings may not provide a safe stopping margin, especially in conditions of moderate or heavy rain on smooth runways, the Federal Aviation Administration issued SAFO 19003, which replaced SAFO 15009, 2 months after the accident. The new SAFO recommends that pilots verify, before initiating an approach, that the aircraft can stop within the landing distance available using a runway condition of medium-to-poor whenever there is the likelihood of moderate or greater rain on a smooth runway or heavy rain on a grooved/porous friction course runway. The operator’s SOPs would have prohibited landing if runway 10’s surface condition were assigned a value less than “good,” given the existing tailwind at the time of the accident; according to the operator’s SOPs, a “wet” runway is considered to have good braking action. Consequently, the flight crew’s ability to determine whether they could safely land on the runway was critically dependent on their ability to determine that the actual condition of the runway was worse than “good.” Notably, although not directly causal to the accident (because the worse-than-expected runway friction prevented the airplane from stopping on the runway), the airplane’s approach to NIP did not meet the operator’s stabilized approach criteria by the time the airplane descended to 1,000 ft agl, and several cues should have led the flight crew to call for a missed approach as required by SOPs. The airplane’s airspeed exceeded the target approach speed, it was above the glidepath, and its descent rate was greater than 1,000 fpm, which prompted multiple sink rate alerts that should have induced the flight crew to call for a missed approach. Additionally, the Miami Air Flight Operations Manual (FOM) required a flight crew to initiate a missed approach if the aircraft was not stabilized by 1,000 ft. At the time of the accident, the first officer had only 18 hours in the Boeing 737 and most of his previous experience was operating light aircraft. Thus, his lack of experience flying jet aircraft likely played a role in his inadequate monitoring of the approach (his lack of experience was also exemplified by his failure to note, as part of his monitoring duties, that the speedbrake handle had not been armed after calling the item as part of the Landing checklist). The captain’s continuation of the approach, contrary to the operator’s stabilized approach criteria, was likely due to a combination of factors. The first was plan continuation bias (an unconscious cognitive bias to continue with the original plan despite changing conditions). The captain’s bias may have been reinforced by a self-induced pressure to land because the flight was late due to an earlier maintenance delay and, the captain and the first officer were approaching the end of their legal duty day. A go-around or diversion to an alternate airport would have caused additional delays. Another factor was the captain’s increased workload during the approach. Flying and monitoring duties are typically divided to reduce workload for each crewmember. However, cockpit voice recorder data indicate that, rather than relay queries or responses to ATC through the first officer, the captain made multiple radio communications to the approach controller regarding the weather, despite the first officer being responsible for performing this task as part of his monitoring duties. In addition to performing some of the first officer’s radio duties, the captain was also performing check airman duties in a bad weather situation. Further, the captain’s failure to check that the speedbrake handle was armed, as part of the Landing checklist, was an oversight that was likely another result of his increased workload. Combined with plan continuation bias, the captain’s increased workload from performing additional tasks narrowed his attention and limited his ability to recognize and correctly respond to the cues of an unstabilized approach.
HISTORY OF FLIGHTOn May 3, 2019, at 2142 eastern daylight time, Miami Air International flight 293, a Boeing 737-81Q, N732MA, departed the end of runway 10 while landing at Jacksonville Naval Air Station (NIP), Jacksonville, Florida, and came to rest in shallow water in St. Johns River. Of the 2 pilots, 4 flight attendants, 1 mechanic (in the jumpseat), and 136 passengers onboard, one minor injury was reported; the rest were not injured. The airplane was substantially damaged. The flight was operated as a Title 14 Code of Federal Regulations Part 121 supplemental nonscheduled passenger flight from Leeward Point Field (MUGM), Guantanamo Bay, Cuba, to NIP. Marginal visual flight rules conditions prevailed at the time of the accident. According to the flight crew, the day of the accident was the second day of a 3-day pairing; three flight legs were scheduled for the day; however, the schedule was amended before the accident flight to remove the originally scheduled third (last) leg of the day due to earlier maintenance delays. The pairing was the first time the pilots had flown together. The captain was the pilot flying (PF) for the accident flight, and the first officer was the pilot monitoring (PM). The captain was also performing check airman duties for the first officer who was in the process of completing operating experience training. Before departing MUGM, the flight crew reviewed the dispatch paperwork and weather and noted that thunderstorms were in the forecast for their scheduled time of arrival at NIP; Orlando International Airport, Orlando, Florida, was listed as the alternate airport. The No. 1 (left) thrust reverser was not operational and deferred for the flight in accordance with the airplane’s minimum equipment list (MEL). According to both pilots, the takeoff, climb, and cruise portions of the flight were uneventful. During postaccident interviews, the flight crew stated that, about 30 minutes before landing at NIP, the flight deviated around weather as it approached the Jacksonville area. According to the captain, the weather was “nothing serious.” Available weather data near this time indicated rain showers or thunderstorm growth over NIP from 2110 onward. Based on the weather forecast information provided in the flight plan, which indicated variable wind at 20 knots with 30-knot gusts, thunderstorms, and rain, the flight crew set up the area navigation (RNAV) GPS approach to runway 10 in the flight management system and briefed setting the autobrake at level 2. According to data from the cockpit voice recorder (CVR), about 2122, the first officer checked in with the Jacksonville International Airport (JAX) airport traffic control tower radar approach (RP) controller indicating the flight’s altitude at 13,000 ft mean sea level (msl). The RP controller acknowledged and advised the flight to expect the RNAV approach to runway 28 at NIP, which the first officer acknowledged. About 10 seconds later, the JAX RP controller advised the flight crew of moderate-to-heavy precipitation on the final approach to runway 28. The captain acknowledged and asked about the wind conditions and indicated that he could not pick up the NIP automatic terminal information service (ATIS) (see Airport Information). After checking with NIP airport traffic control tower controllers, the RP controller advised the flight crew that the wind was from 350º at 4 knots. The captain then asked if weather conditions looked better for runway 10. The RP controller responded that, for runway 10, conditions showed moderate-to-heavy precipitation beginning about 5 miles out on the final approach. The captain replied that the flight would continue the approach to runway 28. The RP controller advised the flight crew to descend and maintain at 5,000 ft msl, which the first officer acknowledged. At 2125:45, the RP controller provided additional weather information to the flight crew, stating that moderate-to-heavy precipitation was present east and west of the airport; he asked the flight crew if they wanted to stay with the RNAV approach for runway 28. The captain replied, “ah yes sir, what- whichever looks better an ah then when I get closer I check how it is.” The RP controller assigned the flight crew heading 010 and instructed the pilots to descend to 3,000 ft msl. The flight crew acknowledged and entered the RNAV approach for runway 28 into the flight management system. According to information from US Navy and Federal Aviation Administration (FAA) certified audio ATC recordings, about 2129, the RP controller advised the NIP radar arrival (RA) controller that flight 293 was 15 miles southwest of NIP for the RNAV approach to runway 28. The RA controller responded that the flight was radar identified. About 2130, the RP controller advised the flight crew that the previously mentioned precipitation was moving east and asked if they wanted to change to runway 10. After clarifying the runway number, the captain responded, “yeah go ahead let’s do it.” The RP controller assigned the flight heading 270 then heading 250, which the captain acknowledged. From 2132 to 2133, the JAX RP controller and NIP RA controller coordinated the flight’s change to runway 10. From 2134 to 2137, the RP controller provided the flight crew a series of heading changes to join the final approach course, which the first officer acknowledged. At 2137:34, the RP controller advised the flight crew that they were 7 miles from the final approach fix and cleared the flight for the RNAV runway 10 approach, which the first officer acknowledged. The JAX RP controller also confirmed with the NIP RA controller that the flight was set up for runway 10. At 2137:48, the RP controller instructed the flight crew to contact NIP ground controlled approach (GCA). The captain requested a VHF frequency, which the RP controller provided. The first officer contacted the NIP GCA at 2138:32; the NIP RA controller responded with the NIP altimeter setting and advised that the RNAV approach would be using precision approach radar monitoring. (Precision approach radar is a fixed-base primary approach aid used by the US Navy during poor visibility conditions to provide vertical and lateral guidance, as well as range, to aircraft on final approach). The RA controller also provided rollout and missed approach instructions and advised the flight crew that the short-field arresting gear on runway 10 was rigged (according to a Miami Air operations bulletin, arresting gear on runways places no limitations on Boeing 737 takeoff or landing operations; see Airport Information). The first officer acknowledged, then the captain sought clarification, asking the RA controller, “and that’s for the ah first thousand feet, correct?”, which the RA controller confirmed. While the RA controller was providing arrival instructions, the CVR recorded a sound consistent with an altitude alert at 2139:06. At 2139:38 the NIP radar final (RF) controller assumed control of the flight from the RA controller and advised the flight crew that the “wheels should be down” (ATC procedures at US military facilities require a wheels-down check before descent on final approach for aircraft conducting radar-monitored approaches). The first officer acknowledged, and the CVR recorded sounds consistent with landing gear extension at 2139:48. At the same time, the RF controller cleared the flight to land on runway 10 and indicated a wind direction of 240º at 10 knots. The first officer acknowledged the landing clearance. A sound consistent with an altitude alert was recorded again at 2140:04. At 2140:15, the RF controller advised the flight crew that they were “well above” the 3º glidepath to runway 10; at 2140:25, the precision approach path indicator (PAPI) lights would have appeared to the flight crew as four white lights, indicating the airplane’s glidepath exceeded 3.5º. Automatic dependent surveillance-broadcast (ADS-B) and flight data recorder (FDR) data indicated that the airplane was about 3.5 nautical miles (nm) from the runway 10 displaced threshold about this time and was descending through 1,390 ft msl (1,369 ft above the touchdown zone elevation of 21 ft) at an indicated airspeed of 158 knots and descent rate of 1,062 ft per minute (fpm). The airplane’s true airspeed about this time was 167 knots, and the groundspeed was 174 knots due to a 7-knot tailwind. According to the Boeing 737 flight crew operations manual (FCOM), the flaps 30 landing reference speed (VREF30) was 148 knots calibrated airspeed at the airplane’s landing weight of 143,200 lbs, and the target approach speed (VREF30 + 5 knots) was 153 knots calibrated airspeed (which is the indicated airspeed of an aircraft that is corrected for position and instrument error). At 2140:25, a sound consistent with the autopilot disconnect warning was recorded. The airplane’s descent rate increased from 1,100 to 1,400 fpm at 2140:30. At 2140:31, the captain called for the Landing checklist, and the first officer responded, “ah…speedbrakes ah armed, landing gear down three green, flaps thirty.” At 2140:40, the airplane was about 1,100 ft msl and about 2.8 nm from the runway 10 displaced threshold; its descent rate decreased to 1,000 fpm, its indicated airspeed decreased to the target approach speed of 153 knots, and the groundspeed decreased to 166 knots. The airplane was closer to the nominal 3° glidepath, and the PAPI would have appeared as three white lights and one red light. Between 2140:46 and 2141:39, the indicated airspeed increased steadily from 153 to 170 knots, and the groundspeed increased from 166 to 180 knots. According to the NTSB Performance Study, both groundspeed and airspeed increased during this time at approximately the same rate. Therefore, this increase was a result of pitch control inputs. At 2141:09, at an altitude of about 680 ft msl and about 1.6 nm from the displaced threshold, the airplane deviated further above the 3° glidepath such that the PAPI lights would have appeared to the flight crew as four white lights and would retain that appearance throughout the rest of the approach. For most of the approach from an altitude of 1,400 ft msl (3.5 nm from the displaced threshold) to the displaced threshold, the airplane was offset about 100 ft to the right of the extended runway centerline. At 2141:17, when the airplane was about 1 nm from the displaced threshold, its roll angle dipped to 12° right, and the airplane deviated farther to the right. This deviation reached 220 ft right of the runway centerline at 2141:28 when the airplane was about 0.5 nm from the displaced threshold and at an altitude of 360 ft msl. The airplane then rolled to about 9° left and corrected back toward the centerline. From 2141:18 to 2141:38, the airplane’s flightpath angle steepened from -2° to -5°. Six enhanced ground proximity warning system (EGPWS) “sink rate” alerts were recorded on the CVR starting at 2141:35 and ending at 2141:42; the descent rate peaked at 1,580 fpm about this time. The airplane crossed the displaced threshold at 2141:38, at an altitude of 140 ft msl (about 120 ft above the runway), an indicated airspeed of 170 knots (17 knots above the target approach speed), a groundspeed of 180 knots, and a descent rate of 1,450 fpm (according to Miami Air’s stabilized approach criteria, the descent rate should not exceed 1,000 fpm below 1,000 ft above field level). According to the NTSB Performance Study, during the approach, the tailwind averaged about 5 knots until a few seconds before touchdown, when the tailwind increased to about 12 -13 knots, possibly as a result of the wind veering into the west and providing a more direct tailwind component. Touchdown occurred at 2141:43.1, about 20 ft right of centerline, 1,580 ft past the displaced threshold and 394 ft beyond the runway’s short field arresting gear; according to the FCOM, the target touchdown point is 1,000 ft from the threshold and “should occur within -250 ft to +500 ft of the target touchdown point). At touchdown, the airplane’s indicated airspeed was 164 knots (11 knots above the nominal approach speed), and the groundspeed was 180 knots. After touchdown, the airplane moved left until reaching 10 ft left of centerline then started moving back toward the right. FDR data indicate that No. 2 (right) throttle idle reverse thrust was commanded at 2141:46. At 2141:47, about 4 seconds after touchdown, the speedbrake handle moved aft to 46° and the speedbrakes deployed. Detent 2 reverse thrust (the position specified for normal operations in Miami Air’s operations manual) was commanded about 2141:48. FDR data indicate that the autobrakes were applied at 2141:48 then pressure from the left normal (manual) brake metering valve increased to 905 lbs per square inch and, by design, disengaged the autobrakes at 2141:49. The brakes were manually controlled by the flight crew for the remainder of the landing. The captain stated during postaccident interviews that he applied brake pressure after touchdown, but the airplane did not decelerate. He did not notice any antiskid activation. He stated he also deployed the No. 2 engine thrust reverser and applied enough pressure to the thrust reverser lever that it left a mark on his fingers. He stated that the airplane began to “slide a little to the right” and that he corrected with rudder to get the airplane back on centerline. The airplane crossed the runway centerline from left to right at 2141:50.3, about 3,650 ft past the displaced threshold and 2,070 ft past the touchdown point. Between 2141:55 and 2141:58, maximum reverse thrust was commanded on the No. 2 engine. Between 2141:59 and 2142:00, the right throttle moved briefly back to the forward idle thrust position and the right thrust reverser temporarily stowed. Maximum reverse thrust on the No. 2 engine was again commanded at 2142:02 and was maintained until 2142:12, when the reverse thrust was reduced to the detent 2 level where it remained until the end of the data. The airplane began moving back toward the centerline and was about 55 ft right of the centerline when it crossed the end of the runway at 2142:10.4, 8,006 ft past the displaced threshold. After departing the paved surface, the airplane impacted the seawall at 2142:19.2; it was 90 ft to the right of the centerline, 9,170 ft past the displaced threshold, and 1,164 ft past the end of runway 10. The first officer stated during postaccident interviews that, after the airplane came to rest, the captain called for an evacuation. During postaccident interviews, the captain stated that he never thought to call for a go-around and that, as far as he knew, the runway was not contaminated. He stated that he “had his hand on the [weather] radar a couple of times” during the approach; however, there was not a “solid line” of weather, and he could see the city in the distance. He also stated that it started raining “very hard” on short final approach and that he turned on the wipers. The first officer stated that they visually acquired the runway lights about 3 to 4 miles outside the final approach fix. He also stated that about 1 mile from the runway, the flight encountered a “rain shower” and that the airplane drifted to the right. In response, the captain corrected back to the extended centerline. Both pilots stated that none of the ATC communications included runway condition or braking action reports, and, according to CVR data, neither pilot requested this information. According to the mechanic who was seated in the jumpseat, he could see the runway lights, but he could not recall how far out on final approach they were when he first saw them. He recalled they were in “heavy rain” and the captain had turned on the wipers to the highest setting. Other than the reverser light on the overhead panel, the mechanic did not observe any lights in the cockpit during the approach or after the airplane landed. When asked, he did not recall seeing the green auto arm light for the speedbrake illuminate. A flight crew that was scheduled to take flight 193 passengers to Norfolk Naval Station, Norfolk, Virginia, was in an airplane parked on the ramp when flight 293 landed. The captain for the Nor
An extreme loss of braking friction due to heavy rain and the water depth on the ungrooved runway, which resulted in viscous hydroplaning. Contributing to the accident was the operator’s inadequate guidance for evaluating runway braking conditions and conducting en route landing distance assessments. Contributing to the continuation of an unstabilized approach were 1) the captain’s plan continuation bias and increased workload due to the weather and performing check airman duties and 2) the first officer’s lack of experience.
Source: NTSB Aviation Accident Database
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