On 27 August 2006, a Bombardier CRJ100 (N431CA) being operated by Comair on a scheduled passenger flight from Lexington KY to Atlanta GA as flight 5191 attempted to take off in normal night visibility from unlit runway 26 instead of runway 22 as cleared. The length of runway 26 was insufficient and the aircraft overran and was destroyed by impact forces and a post crash fire. All but one of the 50 occupants died - the First Officer survived with serious injuries.
The airport layout [reproduced from the Official Report]
An Investigation was carried out by the NTSB. The FDR and 30 minute CVR were recovered from the wreckage and almost all of the potentially useful data they contained were successfully downloaded. The recording intervals for two parameters did not comply with the applicable regulations in a way that the Board had found in other regional jet investigations and a previous Safety Recommendation on this subject was re-iterated and re-classified whilst this Investigation was in progress.
No evidence was found that either the prevailing weather conditions or any related lack of aircraft airworthiness had been relevant to what happened. However, it was noted that the attempted takeoff had occurred about an hour prior to sunrise in the absence of any moonlight.
It was found that the 35 year-old Captain had done all his multi crew flying with Comair, having joined the Company a little over 5 years prior to the accident as a First Officer and had been promoted to Captain in January 2004. He had 4,710 hours total flying experience which included 3,082 hours on type. The 44 year-old First Officer had joined Comair a little over 4 years prior to the accident and had 6,564 hours total flying experience which included 3,564 hours on type. He was acting as PF for the accident flight sector. It was noted that both pilots had departed from Lexington on a few previous occasions including at night, but also that at the time of the accident, the airport was close to completing a "multiyear construction project" which had involved changes to the taxiway access to runway 26. Whilst the accident aircraft was being prepared for departure and during its taxi out and attempted takeoff, the ATC facility was staffed with just one controller covering Tower and Radar positions. He had been working at the airport for 17 years and was approaching the end of his rostered night shift at the time of the accident.
It was established that having called ready to taxi with the taxi and takeoff briefings completed, the flight was instructed to taxi to the 2135 metre-long runway 22 - an instruction which authorised the aircraft to cross the landing threshold of the intersecting 1067 metre-long VFR/day-use-only runway 26 without stopping (see the illustration below). Both pilots had the heading bugs on their respective PFDs and MFDs set to 227°, the runway 22 centreline.
Taxiway A leading to runway 26 (on the left) and continuing to runway 22. [Reproduced from the Official Report]
FDR data indicated that the Captain, who taxied the aircraft from the parking position until it was lined up on runway 26, had initially stopped the aircraft at the runway 26 holding point. During that short taxi - just over two minutes - the CVR record showed that in addition to completing the Taxi Checks and beginning the Before Take Off checks, the two pilots had, for a period of 40 seconds, engaged in "non-pertinent conversation" contrary to the Comair requirement for a sterile flight deck during taxi out and take off. Once stopped, the First Officer had made a welcome PA to the passengers and then completed the Before Takeoff Checklist. With the aircraft still at the runway 26 holding point, the First Officer then reported to ATC that the flight was ready to depart (using the identification “Comair 121" instead of 191) and the controller responded, "Comair 191.....fly runway heading, cleared for takeoff". Neither the First Officer nor the Controller included the runway number in their transmissions.
Without delay, the Captain began to taxi the aircraft across the holding point and turned left so that it was, according to FDR data, aligned on about 226°M, the runway 26 centreline, and stopped. Whilst he was doing this he called for the Line Up checklist which was complete by the time the aircraft had stopped. The Captain was recorded as saying "all yours" and the First Officer responded with "my brakes, my controls" and the takeoff roll began a few seconds later. Eight seconds before the standard "100 knots" call from the Captain, the First Officer was recorded saying "(that's) weird with no lights” to which the Captain responded "Yeah". 7 seconds after the 100 knots call, at a recorded speed of 131 knots - 6 knots ahead of the planned V1 and 11 knots ahead of the planned VR - the Captain called " V1, rotate" followed almost immediately by "whoa" upon which the First Officer immediately pulled his control column fully aft at a rate of about 10° per second - about three times the normal rate.
The aircraft hit a 4 foot high earth bank about 80 metres beyond the end of runway 26 and became temporarily airborne after impact but reached less than 20 feet agl before impacting a tree about 275 metres beyond the end of the runway at the maximum recorded forward speed of 137 knots. The CVR recording ended soon afterwards, with three seconds having elapsed since impact with the earth bank.
The controller subsequently stated that before issuing the takeoff clearance, he had checked that runway 22 was clear but had not checked the aircraft position or then monitored the takeoff roll. After hearing a sound, he reported having looked up and seen a fire to the west of the airport and had immediately activated the crash alarm and advised of an aircraft accident, indicating to the airport operations that "a Comair jet taking off from runway 22" was located at the west side of the airport just beyond the end of the runway.
The aircraft was quickly destroyed by a combination of the effects of obstacle impact and the post crash fire which quickly began. The fuselage had separated into two main sections, and both wings had separated from the fuselage. None of the exits had been opened. The first two airport personnel to reach the crash site reported having located the fuselage almost 10 minutes after the crash had occurred and were able to extricate the First Officer from the wreckage after which he was taken directly to hospital in one of the available vehicles. Two ARFF vehicles arrived soon afterwards and began to "knock down" the fire which was brought under control within about 3 minutes, but no other occupants could be rescued.
The aircraft manufacturer provided the Investigation with accelerate-stop performance calculations for runway 26 assuming maximum braking which showed that to stop before reaching the end of the runway, deceleration would have had to have begun at a speed not above 103 knots. In addition, it was calculated that the aircraft would require more than the available length of runway 26 to reach the V1 speed calculated by the crew.
It was found that a NOTAM advising of the closure of the previous taxiway A access to the full length of runway 22 beyond runway 26 and the re-designation of the previous taxiway A5 as the new continuation of taxiway A had been in effect for a week when the accident occurred. However, the crew had the current Jeppesen chart which showed the previous access with taxiway A continuing from the 26 threshold to runway 22 with a 45° left turn rather than a 90° one and the changes were not mentioned in the flight release paperwork or on the ATIS. In the absence of the latter, the Investigation concluded that "the controller's direct communications with the pilots" should have highlighted this. Nevertheless, it was noted that "even though discrepancies existed between the airport chart and the external cues available to the pilots.....the chart depicted the paved taxiway and runway surfaces at the time of the accident".
The Investigation reviewed the crew actions prior and during the taxi out in detail. Prior to taxi, Comair Standard Operating Procedures (SOPs) required that the Captain should conduct a pre-taxi briefing and that for any first flight of a flight crew such as this one, that briefing must be a detailed one, given with both pilots having the appropriate airport diagrams available and with explicit attention given to any runway crossings. Contrary to this, the Captain gave this briefing as "Comair Standard", an option only available for subsequent flights in a same-crew sequence. However, it was noted that despite this, there had then been "multiple and more salient cues...to aid the flight crew while navigating to the runway" given that the taxi route was "relatively simple" and the crew were aware it was only a short taxi. Nevertheless, it was considered significant that when giving the takeoff briefing soon after this, the First Officer did "not brief that the taxi to runway 22 required crossing runway 26" and the Investigation "was unable to determine why this was so". It was considered possible that "the simplicity of the taxi and the use of only one taxiway might have led him to assume that it was unnecessary to include this additional information". Other pilots indicated that they too would brief this "short taxi" in a similar manner and no evidence was found that the pilots were unaware of the need to cross runway 26 to get to runway 22. However, it was considered that neither of the accident aircraft pilots had sufficient experience of operations into and out of the airport to allow them to have memorised taxiway identifiers and routes.
From the controller's perspective, it was acknowledged that since the two aircraft that had departed from runway 22 ahead of the accident aircraft had already taxied correctly to and held short of runway 22 without any special instructions being given, there was no reason why the controller might have anticipated that the Comair pilots would have had any difficulty doing the same thing. He stated that he did not routinely monitor compliance with taxi out routing or takeoffs once he had given clearance and on this occasion, once the take off clearance had been given, he had decided to work an administrative task which needed to be completed before he could go off shift. His shift had begun at 2330 the previous evening and had followed an 8 hour morning shift ending at 1430 earlier in the day. Although he reported having been fully rested prior to the previous days early shift, between the end of this shift and the beginning of the night shift he reported obtained only around 2 hours sleep which was therefore all he had slept in the 24 hours preceding the accident. The possibility of the controller being affected by fatigue in any way that might have had a bearing on the accident was examined but although it was found that he "was most likely fatigued at the time of the accident" not least on account of the evident sleep deficit, no evidence of such an effect was found. There was also no evidence to suggest that the controller's working of both the tower and radar positions in light traffic conditions had resulted in any consequence relevant to the accident.
In terms of the pilots, it was concluded that during the 50 second stop at the runway 26 holding point, both of them had been under the impression that they were at the runway 22 holding point. However, it was considered that this stop should have provided the pilots "ample time to look outside.....and determine the airplane’s position on the airport". From that position, they "would have been able to see the runway 26 holding position sign, the “26” painted runway number, the taxiway A lights across runway 26 and the runway 22 holding position sign in the distance". However, despite the "numerous cues" that the aircraft had not been on the right runway, including but not limited to the complete lack of runway lighting and the presence of continuous painted edge lines restricting the available width to 23 metres compared to the normal 46 metres, neither pilot had noticed anything until it was too late to reject the takeoff.
It was noted that performance of both pilots on the day of the accident was at odds with the observations of their peers who described them both as "competent pilots who had not previously demonstrated difficulty with airport surface operations" and the Captain specifically as someone who managed the flight deck well, followed SOPs and displayed good CRM. More generally, "Comair Captains described CRM training as good (and) Comair First Officers stated that they had no difficulties speaking up if they felt rushed or had concerns with the conduct of the flight". One Comair Training Captain stated that "when First Officers have not spoken up during line checks after a Captain has made an error, it was because of a lack of situational awareness rather than a hesitancy to speak up". Also, the Principal Operations Inspector (POI) for Comair stated that "there had not been a crew interaction problem during the 5 years that preceded the accident".
The possibility of fatigue being a factor in flight crew performance was examined but it was concluded that "even though (they) made some errors during their pre-flight activities and the taxi to the runway, there was insufficient evidence to determine whether fatigue affected their performance". However, it was considered that the various instances where SOPs were disregarded, such as the Captain's abbreviated initial taxi briefing and the failure of both pilots to operate a sterile flight deck, were likely to have "created an atmosphere.....that enabled the crew’s errors".
Safety Action taken as a result of the accident and known to the Investigation included but was not limited to the following:
- On 27 August 2006, a NOTAM was issued to announce the closure of Lexington runway 08/26 and the placing of lighted “X” markings at each end of the runway with effect from 29 August 2006. (The runway remained closed until 1 November 2006 when the new taxiway A7 access to runway 22 was opened.)
- With effect from 8 September 2006, Comair arranged for a note to be attached for every fight release for operations into or out of Lexington warning that published airport diagrams for the airport "may not accurately reflect actual airport signage and markings" and as a consequence to "exercise extreme caution during all ground operations, utilize high threat taxi procedures (and) if unsure of position or taxi clearance clarify with ATC or request progressive taxi instructions". (This note was removed from flight releases with effect from 3 November 2006 after the new taxiway A7 had been opened and the current Jeppesen aerodrome chart accurately reflected the airport configuration).
- On 1 September 2006, the FAA issued Safety Alert for Operators (SAFO) 06013 entitled "Flight Crew Techniques and Procedures that Enhance Pre-takeoff and Takeoff Safety" which discussed techniques, procedures, and items for consideration for training programs that emphasise safe operations in the pre-takeoff and takeoff phases of flight. It also referred to existing FAA guidance on ground operations, such as AC 20-74A (NB: this Circular was cancelled on 30 July 2012) and stated that flight crews should "confirm, using the challenge and response technique, that the aircraft is actually positioned on the assigned runway by reference to the heading indicator" and specifically recommended that pilots should "use all available resources to ensure that the aircraft is positioned on the proper runway". Flight crews of FMS-equipped aircraft were recommended to "verbally announce that the proper runway and departure procedure are selected in the FMS and that the aircraft heading agrees with the assigned runway for takeoff".
- On 17 November 2006, the FAA acting as ANSP modified ATC requirements to "formalise earlier verbal guidance on night shift controller staffing for facilities with both tower and radar responsibilities".
- On 4 January 2007, Lexington ATC introduced a new requirement for all controllers stating that "a takeoff clearance for Runway 22 shall not be issued until the aircraft has been physically observed to have completed a crossing of Runway 26", noting that the requirement represented "an effort to add a layer of safety.… and avoid pilot confusion".
- On 9 January 2007, the FAA issued guidance to Airport Operators which suggested that they should supply detailed information about runway and taxiway closures and airport construction (directly) to air carriers and fixed-base operators on the airport using both text and illustration format.
- On 23 March 2007, the FAA announced that it was accelerating the certification process to facilitate the installation in air carrier flight decks of Class 2 EFBs and their use during ground operations in recognition that requirements for the ground use of these devices could be relaxed compared with the more stringent class C standards for the airborne use of the same EFBs.
- On 16 April 2007, the FAA issued Safety Alert for Operators (SAFO) 07003 entitled 'Confirming the Takeoff Runway' to "emphasise the importance of implementing standard operating procedures and training for flight crews to ensure that an airplane is at the intended runway".
- On 11 May 2007, the FAA issued a formal reminder on the requirement for runway lighting for all night takeoffs in Part 121 operations which also noted that pilots must check NOTAMs for runway lighting outages and taxiway and runway closures, that takeoffs are not permitted on closed runways and that "a pilot must think beyond pertinent NOTAMs because inoperative runway lights do not necessarily cause a runway to be closed by the airport authority". It also cautioned that a lit runway is not necessarily usable.
- On 1 June 2007, the FAA acting as ANSP amended the required phraseology for issuing aircraft departure instructions to include "when issuing a clearance for takeoff, first state the runway number followed by the takeoff clearance (and) if the takeoff clearance is issued prior to the aircraft crossing all intervening runways, restate the runway to be crossed in conjunction with the takeoff clearance". (However, it was noted that this did not instruct controllers to wait until an aircraft has crossed such runways before issuing the takeoff clearance.
The Probable Cause of the accident was determined to have been "the flight crew members’ failure to use available cues and aids to identify the airplane’s location on the airport surface during taxi and their failure to cross-check and verify that the airplane was on the correct runway before takeoff".
Two Contributory Factors in the accident were identified as having been:
- the flight crew’s non-pertinent conversation during taxi which resulted in a
loss of positional awareness.
- the Federal Aviation Administration’s failure to require that all runway crossings be authorised only by specific air traffic control clearances.
A total of eleven Safety Recommendations were made a result of the Investigation as follows: On 12 December 2006, two Recommendations were made:
- that the Federal Aviation Administration should require that all 14 CFR Part 121 operators establish procedures requiring all crew members on the flight deck to positively confirm and cross-check the airplane’s location at the assigned departure runway before crossing the hold short line for takeoff. [A-06-83]
- that the Federal Aviation Administration should require that all 14 CFR Part 121 operators provide specific guidance to pilots on the runway lighting requirements for takeoff operations at night. [A-06-84]
On 10 April 2007, four Recommendations were made:
- that the Federal Aviation Administration should work with the National Air Traffic Controllers Association to reduce the potential for controller fatigue by revising controller work-scheduling policies and practices to provide rest periods that are long enough for controllers to obtain sufficient restorative sleep and by modifying shift rotations to minimise disrupted sleep patterns, accumulation of sleep debt, and decreased cognitive performance. [A-07-30]
- that the Federal Aviation Administration should develop a fatigue awareness and countermeasures training program for controllers and for personnel who are involved in the scheduling of controllers for operational duty that will address the incidence of fatigue in the controller workforce, causes of fatigue, effects of fatigue on controller performance and safety, and the importance of using personal strategies to minimize fatigue. This training should be provided in a format that promotes retention, and recurrent training should be provided at regular intervals. [A-07-31]
- that the Federal Aviation Administration should require all air traffic controllers to complete instructor-led initial and recurrent training in resource management skills that will improve controller judgment, vigilance, and safety awareness. [A-07-34]
- that the National Air Traffic Controllers Association should work with the Federal Aviation Administration to reduce the potential for controller fatigue by revising controller work-scheduling policies and practices to provide rest periods that are long enough for controllers to obtain sufficient restorative sleep and by modifying shift rotations to minimize disrupted sleep patterns, accumulation of sleep debt, and decreased cognitive performance. [A-07-32]
On completion of the Investigation, a further five Recommendations were made:
- that the Federal Aviation Administration should require that all 14 CFR Part 91K, 121 and 135 operators establish procedures requiring all crew members on the flight deck to positively confirm and cross-check the airplane’s location at the assigned departure runway before crossing the hold short line for takeoff. This required guidance should be consistent with the guidance in Advisory Circular 120-74A and Safety Alert for Operators 06013 and 07003. [A-07-44]
- that the Federal Aviation Administration should require that all 14 CFR Part 91K, 121, and 135 operators install on their aircraft cockpit moving map displays or an automatic system that alerts pilots when a takeoff is attempted on a taxiway or a runway other than the one intended. [A-07-45]
- that the Federal Aviation Administration should require that all airports certificated under 14 CFR Part 139 implement enhanced taxiway centreline markings and surface painted holding position signs at all runway entrances. [A-07-46]
- that the Federal Aviation Administration should prohibit the issuance of a takeoff clearance during an airplane’s taxi to its departure runway until after the airplane has crossed all intersecting runways. [A-07-47]
- that the Federal Aviation Administration should revise Federal Aviation Administration Order 7110.65, 'Air Traffic Control' to indicate that controllers should refrain from performing administrative tasks, such as the traffic count, when moving aircraft are in the controller’s area of responsibility. [A-07-48]
The Final Report was adopted by the Board on 26 July 2007 and subsequently published.