United Airlines A320 at New Orleans on Apr 4th 2011, smoke in cockpit, complete electronic failure, runway excursion, evacuation

Last Update: December 17, 2020 / 21:23:31 GMT/Zulu time

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Incident Facts

Date of incident
Apr 4, 2011

Classification
Accident

Airline
United

Flight number
UA-497

Aircraft Registration
N409UA

Aircraft Type
Airbus A320

ICAO Type Designator
A320

Airport ICAO Code
KMSY

A United Airlines Airbus A320-200, registration N409UA performing flight UA-497 from New Orleans,LA to San Francisco,CA (USA) with 104 passengers and 5 crew, was in the initial climb when the crew reported smoke in the cockpit, levelled off at 5000 feet and returned to New Orleans. The crew reported before joining downwind that they had lost all instruments and requested to be talked down by ATC via Precision Approach Radar (PAR). The crew descended to 600 feet where they got visual contact with the water of Lake Pontchartrain and continued visually for a landing on runway 19 about 10 minutes after departure. During landing the aircraft blew both right hand main gear tyres, went left off the runway, stopped with all gear just off the paved surface north of the intersection with runway 10/28, and was evacuated via slides.

A number of passengers needed medical attention due to smoke inhalation.

Post landing photos showed the RAM Air Turbine (RAT) deployed. Runway 01/19 was closed for about 10 hours.

The crew told passengers that they had lost all electronics and were flying on minimal backup systems, landing would occur overweight with minimal braking and minimal steering ability.

At the time of the emergency runway 10/28 at New Orleans was not available and was closed. Frantic attempts by tower to get the runway clear during the emergency proved unsuccessful, the runway was cleared and opened about 10 minutes after UA-497 had landed.

The NTSB reported on Apr 4th that the crew received automated warnings and observed smoke in the cockpit while climbing through 4000 feet, subsequently they reported the loss of primary instruments. Upon landing they experienced the loss of anti-skid and nose wheel steering and went off the left side of the runway about 2000 feet down the runway. The right forward slide did not inflate. The NTSB have opened an investigation.

On Apr 6th the NTSB reported the airplane went off the left side of the runway about 2000 feet before the runway end after the aircraft experienced electrical problems and smoke in the cockpit.

On Apr 7th the NTSB said the crew recalled receiving an auto-throttle related ECAM message while climbing through 4000 feet shortly followed by an avionics smoke warning with the instruction to land. Despite this message neither crew recalled smelling smoke or fumes during the flight. The captain worked the electronic checklist for the avionics smoke warning, which included shutting down some of the electrical systems. The first officer's display screens went blank, the ECAM messages disappeared, the cockpit to cabin intercom stopped functioning and the air driven generator (RAT) deployed. The captain took control of the aircraft and managed the radios while the first officer opened the cockpit door to advise flight attendants. The crew requested runway 10 but was advised runway 10 was unavailable due to construction vehicles on the runway. The captain was able to use airspeed, altimeter and attitude information during the return to the airport and ordered an evacuation after landing. Cabin crew did not smell smoke or fumes nor did they observe haze, but noticed the cabin lights were turned off and the intercom ceased functioning. Cockpit Voice and Flight Data recorders were downloaded, they both stopped recording prior to landing.

Following the landing ATIS announced a disabled aircraft 300 feet northeast of the threshold runway 28 (editorial note: putting it 2000 feet before the runway end, also observe the 2000 feet distance marker in the picture below, rather than 2000 feet down the runway).

Some time in the past the NTSB released their final report concluding the probable cause of the accident was:

the captain's failure to properly recognize and manage the abnormal condition, resulting in it escalating to an in-flight emergency.

The NTSB described the sequence of events:

The first officer (FO, 51, ATPL, 11,500 hours total, 1,154 hours on type) was the pilot flying for the flight and the captain (50, ATPL, 15,000 hours total, 1,487 hours on type) was the pilot monitoring. According to flight crew statements and recorded data, the incident flight takeoff began at 0708. At about 0710:10, the cockpit voice recorder (CVR) recorded the captain began the after takeoff checklist and stated, "…wait a minute what do we got here." The captain then states, "okay ECAM I got the uh—uh you got the jet. I got this." The CVR then records the captain beginning the Avionics Smoke ECAM checklist procedure.

The FO stated that about that time he became aware of an "avionics smoke" warning electronic centralized aircraft monitoring (ECAM) message and the captain stated that he noticed a "yellow" autothrust ECAM message. The FO reported he pushed the autothrust (ATHR) button on the mode control panel (MCP), but this did not succeed in re-engaging the autothrust. The captain said the autothrust message was followed by a red "LAND ASAP" ECAM message accompanied by the electrical page synoptic display and the "AVIONICS SMOKE" ECAM procedure.

The FO leveled the aircraft at 5,000 feet in instrument meteorological conditions (IMC) and retarded the thrust levers to slow the aircraft. The captain stated that the first item on the avionics smoke ECAM procedure was to don oxygen masks, but that he and the FO agreed not to don the masks because there was no smell of smoke. The captain did not recall seeing any conditional statements or a timer in the ECAM procedure.

At about 0711:22, the captain stated "line one off" followed by "okay emergency electrical power man on when uh emergency generator available. gen two off." Concurrent with the second generator being switched off, the flight data recorder stopped recording and there was about a six second power interruption of the CVR. When the CVR resumed recording, the captain is discussing the ram air turbine (RAT) and that the airplane is in emergency electrical configuration. The FO then lost his flight instrument displays and began using the captain's primary flight display for altitude, heading and airspeed. A short time later, the captain took control of the airplane.

The FO said that once the captain had taken control of the airplane, he stated that he thought they were in the emergency electrical configuration but he didn't know what the ECAM steps were for that configuration. He said he did not follow up on the ECAM actions, and he did not use the Quick Reference Checklist (QRC) while in flight.

The first officer then tried to alert the flight attendants (FA), but he said he "did not hear the bell" when he called and the FAs did not respond. He used the pedestal handset to call the FA's, but he got no response. He then opened the cockpit door and told the FAs that they were in an emergency and would be landing immediately.

The pilots both stated in interviews that they did not conduct an approach briefing, tune the navigation radios, enter an approach in the FMGC, check the ECAM status page, use the flight manual to determine what systems were affected or lost, conduct an approach descent checklist, conduct an overweight landing checklist, determine the applicable approach speed or landing distance from the FMGC or flight manual, or attempt to repower the electrical system. The captain later said that there was no time to do these things because of the severity of the emergency.

The captain said he knew he would be in direct law with no antiskid or nose wheel steering, but he did not recall telling the first officer this. He estimated that the approach speed should be 160 knots, based on the takeoff V2 of 147 knots, rounded up for wind additive. He said that normal landing distance was 3,500 to 4,000 feet and was confident the airplane would stop on the runway. Both pilots stated that they wanted to keep the approach speed above 140 knots in order to avoid stalling the ram air turbine (RAT).

The captain told ATC that they would need a vector back to the airport and requested "the longest runway." ATC advised that runway 10, which was 10,104 feet long, was still closed due to the equipment on the runway, but that airport personnel were attempting to clear the runway. At about 07:16:03, as the flightcrew lowered the landing gear, the CVR stopped recording.

The captain stated that he could hear the tower on the radio talking to the operations personnel working on runway 10 and he realized that they would not be able to clear that runway in time for the flight to land. The captain then told ATC "we've lost all our instruments, we need a PAR." The captain stated during his interview that he had attitude and compass information but no localizer, and that the screens started to fade during the approach. ATC told the flight that they would provide a no-gyro surveillance approach. The captain did not advise the FO as he continued the descent through the cleared altitude of 2000 feet.

The FO stated that he did not recall if they were cleared to descend out of 2000 feet. According to the ATC recording, the crew reported they "we're at 1000 feet now and we've got water contact, where are we from the airport?" The controller replied that he was at 330 degrees from the airport and said on their present heading they would be "set up for the shoreline 19." After some additional communication with ATC, the captain said "I've got it" and the controller replied "wind 180 at 16 gusts to 20, cleared to land." The captain stated that he landed with full flaps and used the PAPI for vertical guidance.

The captain stated that he landed on the centerline, approximately 1,500 feet down the runway. He also state that he "got on the brakes," used full reverse, and used right rudder to keep the airplane in the center of the runway. The FO stated that on touchdown the cockpit door swung open and that he turned and shouted "remain seated, remain seated." He said that when the engines came out of reverse the captain went to the tiller but the aircraft pulled to the left. The captain had said "I can't control it," and "we're going to evacuate." The airplane continued to veer to the left and the captain indicated he stepped harder on the right brake pedal. The airplane departed the left side of runway 19 approximately 5000 feet from the threshold at a low speed, and the nose gear sank into the soft groundoff the side of the runway.

Once the aircraft came to a stop, the flightcrew used the QRC to conduct the evacuation. The captain set off the evacuation signal and the first officer then silenced it. The first officer said the 1R slide did not inflate and he yelled "go the other way." He went down the 1L slide and began helping the passengers get away from the airplane. The captain came out a few minutes later with a megaphone, which he used to direct the passengers away from the aircraft.

The NTSB analysed:

According to flight data recorder (FDR) data, the Avionics Smoke warning was active at the time the recording began. Since the caution was inactive at power up, it was most likely caused from contaminants detected before the airplane was powered up. Based on this, when the crew arrived at the airplane, they should have had three primary cues alerting them of an Avionics Smoke event, including: a master caution light illuminated amber; an amber AVIONICS SMOKE warning on the upper Electronic Centralized Aircraft Monitor (ECAM); and Blower and Extract fault lights and Gen 1 Line smoke light illuminated amber on the overhead panel. In addition, when they viewed the status page of the ECAM (as required per the captain's Cockpit Preparation checklist), VENT BLOWER and VENT EXTRACT would have been listed under inoperative systems. It is unlikely that airline personnel would have cleared or canceled this warning without communicating this information with the crew, and the crew stated that they did not cancel the warning. Had the warning been inadvertently cleared or cancelled, the overhead panel lights would have remained illuminated and vent blower and vent extract would have remained inoperative systems. Because the cockpit voice recorder (CVR) did not contain any discussion related to any Avionics Smoke event while on the ground, or after takeoff prior to about 1500 feet (during which time both crewmembers responded with surprise), it is unlikely that the crew had previously seen the warning but purposefully ignored the available cues. It is also possible that the crew did not see the cockpit indications since the captain did not complete at least one step of his cockpit preparation checklist–pushing the recorder ground control switch. Because of this, the CVR and FDR did not begin until the time that the APU started, when it should have started much sooner in the sequence of preflight events. So, the investigation was not able to determine whether the crew completed other checklist items that should have alerted them to the Avionics Smoke warning. Finally, investigators were unable to find any condition in which the caution could be recorded on the FDR but not displayed to the crew. Therefore, although the incident flight crew was not aware of the Avionics Smoke event prior to takeoff, investigators could not determine the reason for this.

At 7:10:08.7, the captain began the after takeoff checklist. Item 3 of that checklist is "ECAM memo…checked." When completing this step, the captain detected the Avionics Smoke event on the upper ECAM. Primary cues available were the Avionics Smoke procedure and an amber LAND ASAP message. Although the crew were surprised when they noticed the alert message, there was no corresponding master caution aural warning during this time, which confirms that the Avionics Smoke alert had been active prior to takeoff. The captain then delegated crew duties, assigning the first officer as the pilot flying and indicated that he would complete the ECAM. At 07:10:30.8, the captain began the Avionics Smoke ECAM procedure and stated, "perceptible smoke", referring to the first conditional statement of the procedure "if perceptible smoke". Airbus stated that completion of the Avionics Smoke procedure is dependent on "direct detection by the crew [and] secondary detection by a detector which is considered as a help." Detection by crew can be by sight or smell. According to the procedure, "If perceptible smoke" is a conditional statement and if the crew did not detect smoke, they were not to continue the procedure. After the incident the first officer stated that if Avionics Smoke was detected by the sensor, then there was Avionics Smoke and he was not going to question that.

About 38 seconds after the flight crew became aware of the Avionics Smoke warning, the captain stated, "hey you lost your autopilot too." The FDR indicated that the crew received an autothrust message. CVR data suggests that the captain became very apprehensive about the situation. The flight crew concluded that the failure of the autopilot meant that their situation was deteriorating and they needed to land the airplane promptly. Likely adding to the captain's apprehension was the LAND ASAP [i.e. as soon as possible] message displayed on the ECAM. Although an amber LAND ASAP message was presented, discussions with UAL instructors and pilots indicated that, to a pilot, land ASAP means land ASAP, regardless of color. After the incident, the captain stated that during his last proficiency training session, in-flight fires were emphasized. Specifically, pilots were told that delaying landing by a few minutes could be the difference between a successful landing and loss of an aircraft, such as Swissair [flight 111, that occurred September 2, 1998] and Valujet [flight 592, that occurred May 11, 1996]. The captain said, "he did not want this to be the next Valujet."

The captain continued with the Avionics Smoke procedure but did not do so with the necessary thoughtfulness and made several missed steps. For example, the procedure states action item "EMER ELEC PWR…MAN ON" followed by the conditional statement "WHEN EMER GEN AVAIL:" and action item "GEN 2…OFF". In this instance, the captain should have turned on the emergency electrical power (i.e., deployed the RAT13), and then when emergency generator power was available turned off generator 2. Data show that the captain did not manually deploy the RAT prior to turning off generator 2. As a result, when generator 2 was turned off prematurely, there was a brief disruption in the power supply and the airplane entered the emergency electrical configuration. The EMER ELEC procedure and a red LAND ASAP message appeared on the ECAM. This configuration caused the RAT to automatically deploy which restored electrical power to the airplane after about 6 seconds. The airplane remained in the emergency electrical configuration. Therefore, the captain became apprehensive about the Avionics Smoke event and hastily performed the ECAM procedure resulting in the airplane entering the emergency electrical configuration.

At 7:12:51.5, the first officer alerted the captain that he had no instruments. Two seconds later the captain took control of the airplane and told the first officer to call the flight attendants. The flight crew did not adequately transfer control of the airplane – the first officer did not brief the captain on the status of the airplane and the captain did not brief the status of the emergency procedures. Over the next two and a half minutes the crew focused primarily on contacting the flight attendants and did not discuss completing the EMER ELEC procedure. About 30 seconds later, the flight crew lowered the landing gear without restoring power to the airplane, per the EMER ELEC procedure, and the airplane began operating on battery power. As a result, the CVR recording ended and no further communications in the cockpit were available with the exception of ATC communications. Completion of the EMER ELEC procedure would have restored power to generators 1 and 2 prior to landing gear extension and maintained electrical power to the airplane. After the incident, the captain said when they lowered the landing gear, operating on battery power was not on his mind.

After touchdown, reverser 2 did not deploy, and the airplane veered to the left and exited the runway. The flight crew was not aware that reverser 2 was an inoperative system based on the electrical configuration of the airplane. Had the first officer checked the ECAM status per the Approach Descent Checklist, the inoperative system would have been identified. However, this was not completed likely due to the time constraints. After landing, engine status cues would have alerted the first officer that reverser 2 did not deploy and he should have informed the captain. While it is unknown if the first officer monitored engine status and made the required reverser call out after landing, staff believes it is unlikely because the captain stated in a post incident interview that the airplane departed the runway because of a crosswind. Therefore, the flight crew became distracted by the emergency and focused on landing the airplane without completing necessary checklist items, resulting in the airplane operating on battery power and partial loss of reverse thrust on landing.

It is the captain's responsibility as a leader to set the tone in the cockpit for the entire flight, and this is even more critical when a crew is faced with an abnormal situation. CVR data suggests the tone in the cockpit was very casual. For example, prior to performing the before takeoff checklist, the first officer asks the captain "ready to read em and weep?" And just before takeoff, the first officer stated, "let's get…outta here man." The captain then stated "Brakes released. You got it man. Throttles yours. Whatever you want to do." The casual tone in the cockpit during preflight activities and the taxi did not support the creation of a functional team environment conducive to the crew's subsequent attempts to resolve the abnormal situation. This was manifested in the crew's undisciplined management of the situation in that they failed to adequately assess and understand the situation they were presented with. For example, as the captain completed the after takeoff checklist, he noticed the Avionics Smoke warning on the ECAM; however he failed to announce what the warning was. Instead, he delegated the first officer to fly the airplane and stated he would complete the ECAM. There was no discussion between crewmembers about the situation they were faced with. It is not clear if the first officer was aware of what the warning on the ECAM was. Once the airplane entered the emergency electrical configuration, the captain stopped managing the emergency and the crew's coordination deteriorated further. After the captain stated they were in emergency electrical configuration, the first officer stated "yup confirm. Let's go back." Had the captain been properly managing the abnormal, and now emergency, situation, he should have made the decision to return to the airport rather than the first officer making that decision. In addition, the captain abandoned the EMER ELEC procedure and his pilot monitoring duties. He made radio calls to ATC requesting vectors back to the airport and declaring an emergency. Upon recognizing that the first officer did not have any instruments, the captain assumed control of the airplane. At no point did he delegate the first officer to complete the EMER ELEC procedure but only to inform the flight attendants of the emergency. Completing the EMER ELEC procedure would have resulted in power restoration prior to lowering the landing gear and maintained full use of reverse thrust on landing. After the incident, the first officer stated he did not feel that he had time to be aware of the captain's actions when acting as the pilot flying and said he "took for granted" that the captain completed the ECAM procedure. Finally, during the transfer of flight duties from the first officer to the captain, the first officer stated, "I got the radios", however, subsequent radio communications were made by both crewmembers. Therefore, the captain's failure to set the tone in the cockpit and ineffective management of the emergency resulted in neither crewmember fully understanding the situation they were faced with and subsequent escalation of an abnormal situation to an emergency.



Metars:
KMSY 041353Z 18019G25KT 6SM HZ BKN021 OVC026 25/21 A2984 RMK AO2 PK WND 18026/1330 SLP106 T02500206
KMSY 041253Z 18016G23KT 6SM HZ SCT017 BKN023 24/21 A2984 RMK AO2 SLP106 T02440206
KMSY 041153Z 18015G22KT 7SM FEW015 BKN025 24/20 A2984 RMK AO2 SLP108 T02390200 10244 20239 55004
KMSY 041124Z 18014G20KT 8SM FEW015 BKN025 24/21 A2984 RMK AO2
KMSY 041053Z 18013KT 8SM FEW016 BKN030 24/21 A2984 RMK AO2 SLP107 T02440206
Incident Facts

Date of incident
Apr 4, 2011

Classification
Accident

Airline
United

Flight number
UA-497

Aircraft Registration
N409UA

Aircraft Type
Airbus A320

ICAO Type Designator
A320

Airport ICAO Code
KMSY

This article is published under license from Avherald.com. © of text by Avherald.com.
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