Description

On 14 August 2013, an Airbus A300-60 (N155UP) being operated by United Parcel Service on a scheduled cargo flight (1353) from Louisville KY to Birmingham AL crashed short of the runway at destination during a non precision approach flown at night in Instrument Meteorological Conditions (IMC). The aircraft was destroyed by the impact and post crash fire and both pilots were killed. There was minor damage to local properties

Investigation

An Investigation was carried out by the National Transportation Safety Board (USA) (NTSB). Recorded data relevant to the Investigation was recovered from both the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR).

Details of the A300 type experience of the two pilots showed a considerable difference. The 58 year old Captain had accumulated over 3000 hours on type since 2004 but had only achieved promotion to the rank of Captain in 2009 at the age of 54. Prior to 2004, he had been at UPS since 1990, when he had joined UPS as a Boeing 727 Flight Engineer. The 37 year old First Officer had only 403 hours on the A300, having previously been a First Officer on the Boeing 757 and 747 after initially also joining UPS as a Flight Engineer in 2006.

It was established that the Captain had been PF for what would be a short flight of about 45-50 minutes. Prior to beginning descent, he had briefed for the 18 LOC approach and the First Officer had entered it into the FMC. The intended method of descent was a CDFA using a vertical profile generated by the FMC to provide guidance to the crew after leaving the FAF. This did not alter the decision point for visual transition but simply defined that altitude (1200 feet Altimeter Pressure Settings) as a DA rather than an MDA.

As the aircraft neared the FAF, with the AP engaged, the expected approach clearance to runway 18 was received. However, although the flight plan for the approach had already been entered into the FMC, "the Captain did not request and the First Officer did not verify" that the flight plan reflected only the specified approach fixes and so the direct-to-airport leg that had been set up during the flight from Louisville remained in the FMC. The result was a flight plan discontinuity message in the FMC which rendered the vertical profile generated for the CDFA meaningless. Landing clearance was received and the First Officer actioned the Landing Checklist. The FAF was crossed 200 feet above the published minimum of 2300 feet QNH.

Had the FMC been properly sequenced and the intended vertical profile approach selected, the AP would have followed the anticipated CDFA but this did not occur. Neither pilot recognised what was wrong or that, as a result, the vertical deviation indicator (VDI) was at full scale fly up, although they were aware that they had been slightly high at the FAF. When the AP did not engage in profile mode, the PF selected VS mode - without briefing the First Officer. In effect, in the absence of any prior assessment of the appropriate rate of descent, the approach "essentially became a 'dive and drive' approach where the pilot descends the aircraft to the MDA and levels off until the runway is in sight not later than the specified missed approach point". However, seven seconds after completing the Landing Checklist, the First Officer noticed that the Captain had changed to VS mode and soon afterwards, he increased the VS rate to 1500 fpm. The First Officer made the required 1,000 feet aal call (equivalent to 1530 feet QNH) and the Captain noted that the decision altitude was 1200 feet QNH whilst maintaining a 1500 fpm rate of descent. Since UPS stabilised approach criteria include a maximum 1000 fpm rate of descent at and beyond this point, the effect was a violation of the requirement to go around if not stabilised. At and beyond this point, it was concluded that neither pilot was adequately monitoring the rate of descent - or the altitude.

At 1300 feet QNH, the First Officer failed to make the required 'approaching minimums' call and at 1200 feet QNH, the 'minimums' call. The latter should have elicited either a landing/continuing or go-around response from the Captain. The high rate descent continued and at 1000 feet QNH (about 250 feet aal) an Terrain Avoidance and Warning System (TAWS) 'Sink Rate' alert was annunciated. The PF began to reduce the selected vertical speed to about 600 fpm and, 3.5 seconds later, announced that the runway was in sight. After a further 2 seconds, the PF reduced the selected vertical speed to 400 fpm but the aircraft was still descending rapidly on a trajectory that was taking it to a position about 1 nm short of the runway. Still neither pilot appeared to be aware of the aircraft altitude - or what would have been an abnormal visual perspective. Soon afterwards, the AP was disconnected and almost immediately the sound of the aircraft contacting trees could be heard on the CVR. An EGPWS 'Too Low Terrain' Alert was annunciated and there were several additional impact noises until the recording ended.

An NTSB Video was released after completion of the Investigation to highlight significant human factors aspects of the accident:

The site of the crash in relation to the intended landing runway can be seen in the annotated picture below. It was noted that the crew had expected to become visual at about 1000 feet agl based on the weather reports they had received but in fact had only seen the runway about 5 seconds before contact with the trees began. The vertical profile flown compared to the charted step-down and CDFA procedures is shown on the diagram below the picture.

Using the evidence assembled, the Investigation identified and examined a number of 'Safety Issues' including the following:

• Communications - there were several areas in which adequate communication was considered to have been lacking both before and during the flight. These included the failure of the dispatcher and the flight crew to talk directly to each other even though under the prevailing US licensing and regulatory system, "dispatchers and pilots share equal responsibility for the safety of the flight". Communication between the two pilots during the flight was inadequate and resulted in a lack of shared understanding of how the approach was going to be flown so that the situational awareness of the First Officer was degraded and her role as PM ineffective. Procedural deficiencies in the communication of METARs to UPS crews were also found. These did not contain information about variable ceilings at the destination because the system used by UPS automatically removed the 'remarks' section of these reports and controllers there did not include any 'remarks' in the Automatic Terminal Information Service (ATIS) broadcast, which gave the cloud base as 1000 feet. If they would have had access to the METAR remarks, the pilots might have been more aware of the possibility of the 350 feet agl cloud base that actually prevailed by the time they made their approach.

• Fatigue awareness and off duty responsibilities - a review of the First Officer’s use of her off-duty time indicated "improper off-duty time management" and even though she was aware that she was very tired, she did not call in and report that she was fatigued, even thought there was a procedure to facilitate this.

• Lack of consistency in UPS flight operations documentation - it was found that the various sources of guidance for flight crews including the AOM, the FOM and the Pilot Training Guide (PTG) were not consistent. A number of important procedures were covered only in the PTG, a document not subject to regulatory acceptance or approval so that there is no assurance of pilot training and testing in respect of its procedures.

• Altitude alerting - the accident aircraft was equipped with an EGPWS that could, if activated, have provided an auto callout at 500 feet agl and although it was noted that Airbus operators typically activate the FWC 400 feet alert instead, UPS had not activated either on its A300 fleet. The installed FWC was also capable of generating an auto call out for 'minimums', but UPS had not activated this either.

The Investigation reaffirmed the established view that, when flying non precision approaches, the continuous descent final approach technique provides a safer alternative to the 'dive and drive' technique to which the accident approach had 'degenerated'.

In respect of the way the crew flew the accident approach, it was concluded that:

• The Captain, as pilot flying, should have called for the First Officer’s verification of the flight plan in the flight management computer (FMC), and the first officer, as pilot monitoring, should have verified the flight plan in the FMC; their conversation regarding non-pertinent operational issues distracted them from recognizing that the FMC was not re-sequenced even though several salient cues were available.

• The Captain’s change to a vertical speed approach after failing to capture the prescribed vertical profile was not in accordance with the Operator's procedures and guidance and decreased the time available for the First Officer to perform her duties.

• Neither pilot monitored the rate of descent and the aircraft was flown with a vertical descent rate of 1500 fpm below 1000 feet agl which was contrary to Operator SOPs and constituted an unstabilised approach that should have resulted in a go-around.

• Neither pilot sufficiently monitored the aircraft altitude during the approach and subsequently allowed it to descend below MDA without having acquired the prescribed visual reference.

• The First Officer’s failure to make the “approaching minimums” and “minimums” altitude callouts during the approach probably resulted from the time compression resulting from the excessive descent rate, her momentary distraction from her pilot monitoring duties by looking out of the window when her primary responsibility was to monitor the instruments and contain the effects of her fatigue.

• Although it was the First Officer’s responsibility to make specified callouts during the descent, the Captain was also responsible for managing the approach in its final stages using a divided visual scan that would not leave him solely dependent on the First Officer’s callouts to stop the descent at MDA.

• The Captain’s belief that they were high on the approach and his distraction from his pilot flying duties by looking out of the window probably contributed to his failure to adequately monitor the approach.

• The Captain’s poor performance during the accident flight was consistent with past performance deficiencies in flying non precision approaches which had been noted during training. The errors made during the accident approach were probably the consequence of confusion over why the profile did not engage, his belief that the aircraft was too high and his failure to comply with SOPs.

• The multiple errors which the First Officer made during the flight were probably the result of poor management of her prior off-duty time by not acquiring sufficient sleep and subsequent failure to declared herself unfit to fly due to fatigue as allowed for by the Operator. Once operating, it was considered that the effect of this fatigue had been exacerbated by the unavoidable circadian factors and the effect of time compression and the change in approach modes.

• By not re-briefing or abandoning the approach when the airplane did not capture the anticipated vertical profile after passing the FAF, both pilots placed themselves in an unsafe situation because they had different expectations of how the approach would be flown.

• Whilst the Captain’s adjustment of the aircraft’s vertical speed in response to the EGPWS “Sink Rate” Alert was consistent with Operations Manual guidance and training, it was not consistent with the more conservative guidance contained in the Pilot Training Guide.

In respect of the effectiveness of the safety net against CFIT provided by EGPWS, it was concluded that although newer EGPWS software than that installed in the accident aircraft - P/N 965-0976-003-218-218 or later - would have provided an earlier "Too Low Terrain" Alert (6.5 seconds earlier and 150 feet higher) than that received) the effect of this on the outcome of this accident could not be determined given the high rate of descent and uncertainty about how aggressively the pilots would have responded to it. It was noted that the effectiveness of TAWS as a safety net during the approach to land is limited because an escalating series of Alerts before impact with terrain or obstacles does not necessarily occur.

It was also noted that in respect of the absence of an automatic 'minimums' callout at MDA, either the EGPWS '500' feet callout or the Airbus '400' feet callout could have made the pilots aware of their proximity to the ground and they could have taken more decisive action to arrest the descent.

The Investigation determined that the Probable Cause of the accident was "the flight crew’s continuation of an unstabilised approach and their failure to monitor the aircraft’s altitude during the approach, which led to an inadvertent descent below the minimum approach altitude and subsequently into terrain".

Contributory Factors were identified as:

1. the Flight Crew’s failure to properly configure and verify the Flight Management Computer for the profile (CDFA) approach
2. the Captain’s failure to communicate his intentions to the First Officer once it became apparent the vertical profile was not captured
3. the Flight Crew’s expectation that they would break out of the clouds at 1,000 feet above ground level due to incomplete weather information
4. the First Officer’s failure to make the required minimums callouts
5. the Captain’s performance deficiencies likely due to factors including, but not limited to, fatigue, distraction, or confusion, consistent with performance deficiencies exhibited during training
6. the First Officer’s fatigue due to acute sleep loss resulting from her ineffective off-duty time management and circadian factors

Twenty Safety Recommendations were made as a result of the Investigation as follows:

• that the Federal Aviation Administration require principal operations inspectors to ensure that operators with flight crews performing 14 Code of Federal Regulations Part 121, 135, and 91 subpart K overnight operations brief the threat of fatigue before each departure, particularly those occurring during the window of circadian low. [(A-14-72]

• that the Federal Aviation Administration require operators to develop an annual recurrent dispatcher resource management module for dispatchers that includes participation of pilots to reinforce the need for open communication. [A-14-73]

• that the Federal Aviation Administration require principal operations inspectors to work with operators to ensure that their operating procedures explicitly state that any changes to an approach after the completion of the approach briefing should be re-briefed by the flight crew members so that they have a common expectation of the approach to be conducted. [A-14-74]

• that the Federal Aviation Administration require principal operations inspectors to ensure consistency among their operators’ training documents, their operators’ Federal Aviation Administration 'approved' and 'accepted' documents, such as the aircraft operating manual, and manufacturers’ guidance related to terrain awareness and warning system caution and warning alert responses, and ensure that responses are used during night and/or instrument meteorological conditions that maximise safety. [A-14-75]

• that the Federal Aviation Administration require principal operations inspectors of 14 Code of Federal Regulations Part 121, 135, and 91 subpart K operators to ensure that Federal Aviation Administration-approved non precision instrument approach landing procedures prohibit “dive and drive” as defined in Advisory Circular 120-108. [A-14-76)] (This supersedes A-06-8)

• that the Federal Aviation Administration require that the remarks section of meteorological aerodrome reports be provided to all dispatchers and pilots in flight dispatcher papers and through the aircraft communication addressing and reporting system. [A-14-77]

• that the Federal Aviation Administration expand the current guidance available in Federal Aviation Administration Order 7110.65, “Air Traffic Control,” to further define meteorological aerodrome report pertinent remarks. [A-14-78]

• that the Federal Aviation Administration issue a safety advisory bulletin to air traffic controllers providing examples of the types of meteorological aerodrome report remarks information considered pertinent and reminding them of the requirement to add such pertinent remarks to automatic terminal information service broadcasts. [A-14-79]

• that the Federal Aviation Administration issue a special airworthiness information bulletin to notify operators about the circumstances of this accident and the potential safety improvements related to the Honeywell enhanced ground proximity warning system part number 965 0976-003-218-218 or later software update. [A-14-80]

• that the Federal Aviation Administration advise operators of aircraft equipped with terrain awareness and warning systems (TAWS) of the circumstances of this accident, including that, in certain situations, an escalating series of TAWS warnings may not occur before impact with terrain or obstacles. Encourage operators to review their procedures for responding to alerts on final approach to ensure that these procedures are sufficient to enable pilots to avoid impact with terrain or obstacles in such situations. [A-14-81]

• that the Federal Aviation Administration revise the minimum operational performance standards to improve the effectiveness of terrain awareness and warning systems when an airplane is configured for landing and near the airport, including when the airplane is descending at a high rate and there is rising terrain near the airport. [A-14-82]

• that the Federal Aviation Administration require all operators of airplanes equipped with the automated “minimums” alert to activate it. [A-14-83]

• that the Federal Aviation Administration require, for those airplanes not equipped with an automated “minimums” alert, all operators of airplanes equipped with terrain awareness and warning systems (TAWS) to activate the TAWS 500-ft voice callout or similar alert. [A-14-84]

• that the Federal Aviation Administration require principal operations inspectors of 14 Code of Federal Regulations Part 121, 135, and 91 subpart K operators to verify that procedures critical to approach setup, like configuring an approach in the flight management computer for those approaches dependent on that step, are included in Federal Aviation Administration-approved or -accepted manuals. [A-14-85]

• that the Federal Aviation Administration work with industry, for all applicable aircraft, to develop and implement means of providing pilots with a direct and conspicuous cue when they program the Flight Management Computer flight plan incorrectly (so) that it contains elements such as improper waypoints or discontinuities that would allow the vertical deviation indicator to present misleading information for an approach. [A-14-86]

• that United Parcel Service work with the Independent Pilots Association to conduct an independent review of the fatigue event reporting system to determine the program’s effectiveness as a non-punitive mechanism to identify and effectively address the reported fatigue issues. Based on the findings, implement changes to enhance the safety effectiveness of the program. [A-14-87]

• that United Parcel Service work with the Independent Pilots Association to counsel pilots who call in fatigued and whose sick bank is debited to understand why the fatigue call was made and how to prevent it from recurring. [A-14-88]

• that the Independent Pilots Association work with United Parcel Service to conduct an independent review of the fatigue event reporting system to determine the program’s effectiveness as a non-punitive mechanism to identify and effectively address the reported fatigue issues. Based on the findings, implement changes to enhance the safety effectiveness of the program. [A-14-89]

• that the Independent Pilots Association work with United Parcel Service to counsel pilots who call in fatigued and whose sick bank is debited to understand why the fatigue call was made and how to prevent it from recurring. [A-14-90]

• that Airbus develop and implement, for applicable Airbus models, means of providing pilots with a direct and conspicuous cue when they program the Flight Management Computer flight plan incorrectly so that it contains such elements as improper waypoints or discontinuities that would allow the vertical deviation indicator to present misleading information for an approach. [A-14-91]

The Final Report was adopted on 9 September 2014 and subsequently published. The short video on the link above which discusses some key human factors aspects of the accident was subsequently released on 1 June 2015, the first time NTSB has done this.

Further Reading

• Controlled Flight Into Terrain (CFIT)
• Non-Precision Approach
• Post Crash Fires
• Minimum Descent Altitude/Height (MDA/MDH)
• Continuation Bias
• Terrain Avoidance and Warning System (TAWS)
• Terrain Awareness
• Stabilised Approach
• CFIT Precursors and Defences
• Cross-checking Process
• Runway Visual Perspective
• Situational Awareness
• Fatigue
• Approach Techniques - Flying Stabilized Approaches, Airbus FOBN