BOMBARDIER INC CL-600-2D24

Full Narrative

HISTORY OF FLIGHTOn February 22, 2023, about 1855 pacific standard time (PST), Mesa Airlines (ASH5826), N954LR, a MHI (Mitsubishi Heavy Industry) RJ CRJ-900 and SkyWest Airlines (SKW5326), N619UX, an Embraer ERJ 170-200, were involved in a runway incursion at the Bob Hope Airport (BUR), Burbank, California. The airplanes’ closest point of separation was 1,680 ft which occurred as SKW5326 was departing, while ASH5826 was performing a go-around. There were no injuries reported to the 73 passengers and crew onboard the SkyWest airplane or to the 41 passengers and crew members onboard the Mesa airplane. ASH5826 was operating under the provisions of Title 14 Code of Federal Regulations Part 121 as a scheduled domestic passenger flight from Phoenix Sky Harbor International Airport (PHX), Phoenix, Arizona to BUR. SKW5326 was operating under the provisions of Title 14 Code of Federal Regulations Part 121 as a scheduled domestic passenger flight from BUR to San Francisco International Airport (SFO), San Francisco, California.

About 1853, the BUR local control (LC) controller transmitted SKW5326’s callsign to determine if they had switched from ground control frequency to the LC frequency. The crew responded that they were on the frequency. The LC controller then instructed SKW5326 to turn right on runway 33, back taxi if necessary, and line up and wait (LUAW) for runway 33. The crew read back the instructions as issued. According to the Aircraft Performance Study, at the time SKW5326 was provided LUAW instructions, ASH5826 was 7.9 nautical miles (nm) from the threshold, at 2,800 ft above ground level (agl), and approaching runway 33 at BUR.


Figure 1. BUR Airport diagram depicts the location of runway 33, (purple rectangle) and the air traffic control tower (light blue circle).



Figure 2 provides information on the aircraft locations and associated ATC communications for specific times indicated. The Automatic Dependent Surveillance-Broadcast (ADS-B) flight path data for ASH5826 are shown in orange and SKW5326 are noted in blue.


Figure 2. ADS-B flight paths for ASH5826 (orange) and SKW5326 (blue). Selected times and ATC communications are shown.

At 1853:25, the crew of ASH5826 contacted the BUR airport traffic control tower (ATCT) and reported they were on the visual approach to runway 33.

At 1853:36, the LC advised the crew of ASH5826 that traffic, SKW5326, was holding in position on runway 33 and instructed them to continue the approach. The crew read back the instructions as issued.

SKW5326 entered runway 33 about 1853:45, back taxied, and by 1854:30 the airplane had made a 180° turn, aligned with the runway 33 heading, and stopped behind the runway threshold. According to the SKW5326 captain’s statement, they only had performance data for the full length of the runway, so they back taxied to the beginning of runway 33, did a 180-degree turn, and held at the threshold. They were aware that there was an aircraft on approach to runway 33; however, they did not visually acquire the traffic while back taxiing on runway 33. They were in position and held for what seemed to be a couple of minutes.

At 1855:38, the LC cleared SKW5326 for takeoff from runway 33. The crew read back the takeoff clearance for runway 33, as issued. At this time, ASH5826 was 1.6 miles from the threshold and at 500 ft agl.

At 1855:43, the LC cleared ASH5826 to land runway 33. According to the first officer of ASH5826, he contacted the LC again to confirm they were cleared to land, as the LC had just cleared another aircraft for take-off. At 1855:50, SKW5326 began its take-off roll, and then at 1855:53, the LC responded to the crew of ASH5826, “… affirmative, runway 33 cleared to land.”

According to FAA Order 7110.65Z, the controller was required to apply a 6,000 feet separation between a departing aircraft on its takeoff roll and an arriving aircraft on final approach. The NTSB’s aircraft performance study showed that ASH5826 was 1.6 miles from the runway 33 threshold when SKW5326 was cleared for takeoff.

At 1855:55, one of the pilots on ASH5826 asked if SKW5326, was clear of the runway yet, and subsequently, the other pilot of ASH5826 stated, “no he...we’re going around.” According to the flight crew members of ASH5826, they determined the separation was insufficient and initiated a go-around. At this time, SKW5326 was at a groundspeed of 27 kts and accelerating across the runway threshold, and ASH5826 was 4,200 ft from the threshold and at 300 ft agl.

At 1856:00, the LC stated “roger” and then instructed ASH5826 to climb and maintain 4,000 ft, and fly runway heading. The crew of ASH5826 did not respond. The airplanes were 4,000 ft apart at this time. At 1856:14, the crew of ASH5826 asked the LC for the altitude, and the LC stated 4,000 ft. The crew acknowledged and read back 4,000 ft.

At 1856:27, the LC then instructed the ASH5826 to turn right, heading 270°, and subsequently corrected that instruction by stating “left 270°”. The crew acknowledged and readback left 270°. Both airplanes began a left turn once past the runway’s surface. According to the first officer of ASH5826, as they made the turn, he saw SKW5326 climbing underneath them and they received an audible alert from their onboard traffic alert and collision avoidance system (TCAS).

At 1856:57, the LC instructed the crew of SKW5326 to continue on the standard instrument departure route (SID). The crew read back the instructions as issued.

At 1857:02, the LC instructed ASH5826 to continue their climb. The crew read back the instructions as issued.

At 1857:12, according to the Aircraft Performance Study, and as indicated in figure 3, the minimum separation of 1,680 ft horizontally occurred between ASH5826 and SKW5326.



Figure 3. Flight paths for ASH5826 (orange) and SKW5326 (blue) with times and altitudes.

At 1857:14, the LC asked the crew of ASH5826 if they had the Embraer in sight at 2,500 ft off to their right. The crew stated negative and reported that they were responding to and complying with a resolution advisory (RA). The LC controller responded “roger, turn right 30°”, then corrected that instruction and stated, “left 30°”. The crew acknowledged and readback left 30°.

No further relevant ATC communications occurred between the crew of SKW5326 and BUR. ADDITIONAL INFORMATIONTCAS
The manufacturer of the ASH5826 aircraft was contacted and informed the NTSB that the aircraft contained TCAS, Traffic Surveillance System (TSS) model number 4100 and part number 822-2132-001. The system contained data concentrator unit (DCU) part number 822-1310-007. The operator confirmed this information. With this equipment, the manufacturer informed the NTSB that TCAS Vertical Resolution, which includes parameters TCAS Vertical Control, TCAS Combined Control, TCAS Up Advisory and TCAS Down Advisory, did not record data; therefore, these parameters are not provided.

FAA Order JO 7110.65Z, Air Traffic Control

Chapter 1, Section 1, General, paragraph 1–1–1, Purpose of This Order, stated in part:

This order prescribes air traffic control procedures and phraseology for use by persons providing air traffic control services. Controllers are required to be familiar with the provisions of this order that pertain to their operational responsibilities and to exercise their best judgment if they encounter situations that are not covered by it.

Chapter 2, Section 1, paragraph 2-1-1, ATC Service, stated in part:

a. The primary purpose of the ATC system is to prevent a collision involving aircraft operating in the system.
b. In addition to its primary purpose, the ATC system also:
1. Provides a safe, orderly, and expeditious flow of air traffic.
2. Supports National Security and Homeland Defense missions.
c. The ATC system must provide certain additional services to the extent permitted. The provision of additional services is not optional on the part of the controller, but rather required when the work situation permits. It is recognized that the provision of these services may be precluded by various factors, including, but not limited to:
1. Volume of traffic.
2. Frequency congestion.
3. Quality of surveillance.
4. Controller workload.
5. Higher priority duties.
6. The physical inability to scan and detect situations falling in this category

Chapter 2, Section 1, paragraph 2-1-2 Duty Priority, stated in part:

a. Give first priority to separating aircraft and issuing safety alerts as required in this order. Good judgment must be used in prioritizing all other provisions of this order based on the requirements of the situation at hand.

NOTE- Because there are many variables involved, it is virtually impossible to develop a standard list of duty priorities that would apply uniformly to every conceivable situation. Each set of circumstances must be evaluated on its own merit, and when more than one action is required, controllers must exercise their best judgment based on the facts and circumstances known to them. That action which is most critical from a safety standpoint is performed first.

Chapter 2, section 1, paragraph 2-1-6, Safety Alert, stated in part:

Issue a safety alert to an aircraft if you are aware the aircraft is in a position/altitude that, in your judgment, places it in unsafe proximity to terrain, obstructions, or other aircraft. Once the pilot informs you action is being taken to resolve the situation, you may discontinue the issuance of further alerts. Do not assume that because someone else has responsibility for the aircraft that the unsafe situation has been observed and the safety alert issued; inform the appropriate controller.

NOTE- 1. The issuance of a safety alert is a first priority (see paragraph 2-1-2, Duty Priority) once the controller observes and recognizes a situation of unsafe aircraft proximity to terrain, obstacles, or other aircraft. Conditions, such as workload, traffic volume, the quality/limitations of the radar system, and the available lead time to react are factors in determining whether it is reasonable for the controller to observe and recognize such situations. While a controller cannot see immediately the development of every situation where a safety alert must be issued, the controller must remain vigilant for such situations and issue a safety alert when the situation is recognized.

Chapter 3, section 1, paragraph 3-3-12, Visually Scanning Runways, stated in part:

a. Local controllers must visually scan runways to the maximum extent possible.

b. Ground control must assist local control in visually scanning runways, especially when runways are in close proximity to other movement areas.

Chapter 3, section 9, paragraph 3-9-4, Line Up and Wait (LUAW), stated in part:

a. The intent of LUAW is to position aircraft for an imminent departure. Authorize an aircraft to line up and wait, except as restricted in subparagraph g, when takeoff clearances cannot be issued because of traffic. Issue traffic information to any aircraft so authorized. Traffic information may be omitted when the traffic is another aircraft which has landed on or is taking off the runway and is clearly visible to the holding aircraft. Do not use conditional phrases such as “behind landing traffic” or “after the departing aircraft.”

b. First state the runway number followed by the line up and wait clearance. PHRASEOLOGY-RUNWAY (number), LINE UP AND WAIT.

NOTE- When using LUAW, an imminent departure is one that will not be delayed beyond the time that is required to ensure a safe operation. An aircraft should not be in LUAW status for more than 90 seconds without additional instructions.

Chapter 3, Section 10, paragraph 3-10-3, Same Runway Separation, stated in part:

a. Separate an arriving aircraft from another aircraft using the same runway by ensuring that the arriving aircraft does not cross the landing threshold until one of the following conditions exists or unless authorized in paragraph 3-10-10, Altitude Restricted Low Approach.

2. The other aircraft has departed and crossed the runway end. (See FIG 3-10-4). If you can determine distances by reference to suitable landmarks and the other aircraft is airborne, it need not have crossed the runway end if the following minimum distance from the landing threshold exists:
(a) Category I aircraft landing behind Category I or II- 3,000 feet.
(b) Category II aircraft landing behind Category I or II- 4,500 feet.
(c) When either is a category III aircraft-6,000 feet.

Paragraph 5-8-4 of the order, Departure and Arrival, stated that controllers are to “separate a departing aircraft from an arriving aircraft on final approach by a minimum of 2 miles if separation will increase to a minimum of 3 miles (5 miles when 40 miles or more from the radar antenna) within 1 minute after takeoff.”

Paragraph 5-8-4 also noted the following:
1. This procedure permits a departing aircraft to be released so long as an arriving aircraft is no closer than 2 miles from the runway at the time. This separation is determined at the time the departing aircraft commences takeoff roll.

FAA Order JO 7110.65Z was superseded by JO 7110.65BB on February 20, 2025, but did not change the above information. FLIGHT RECORDERSBoth airplanes were equipped with Flight Data Recorders (FDRs) and Cockpit Voice Recorders (CVRs). The FDR data was obtained for both airplanes, but the incident was overwritten on both airplanes’ two-hour CVRs.

The FDR recorded airplane flight information in a digital format using solid-state flash memory as the recording medium. FDRs receive data in the ARINC 573/717/747 configurations and are required to record a minimum of 25 hours of flight data. FDRs are configured to record a set number of 12-bit words of digital information every second.

The NTSB Vehicle Recorder Division received a L-3/Fairchild FA2100 FDR having part number 2100-2045-22 and serial number 00904855 from Mesa Airlines. Additionally, an electronic file containing the FDR data was received from SkyWest Airlines.

The L-3/Fairchild FA2100 FDR (ASH5826) was configured to record 512 12-bit words of digital information every second and was designed to meet the crash-survivability requirements of TSO-C124b. The FDR was in good condition and the data were extracted normally from the recorder using instructions provided by the recorder manufacturer. The FDR recording contained approximately 154.9 hours of data. The incident flight was the eighth to last flight of the recording, and its duration was approximately 1 hour and 25 minutes. The parameters evaluated for the purpose of this report appeared to be in accordance with federal FDR carriage requirements.

The FDR file obtained from SKW5326 was configured to record 512 12-bit words of digital information every second. The FDR recording contained approximately 140.8 hours of data. The incident flight was the third to last flight of the recording, and its duration was approximately 1 hour and 17 minutes. The parameters evaluated for the purpose of this report appeared to be in accordance with federal FDR carriage requirements.

The latitude and longitude parameters on the FDRs of both airplanes were not recorded with enough precision to accurately determine the airplanes’ locations. Therefore, Automatic Dependent Surveillance-Broadcast (ADS-B) data provided by the FAA was used for the airplanes’ locations. ADS-B broadcasts an airplane’s Global Positioning System (GPS) position and other data to the ground where it is recorded. The GPS position has an accuracy of approximately 20 meters (65 ft) in both the horizontal and vertical dimensions.

However, ADS-B data for SKW5326 was not recorded until the airplane had begun its take-off roll. Its location during taxi was determined using the less accurate FDR data.
HISTORY OF FLIGHTOn February 22, 2023, about 1855 pacific standard time (PST), Mesa Airlines (ASH5826), N954LR, a MHI (Mitsubishi Heavy Industry) RJ CRJ-900 and SkyWest Airlines (SKW5326), N619UX, an Embraer ERJ 170-200, were involved in a runway incursion at the Bob Hope Airport (BUR), Burbank, California. The airplanes’ closest point of separation was 1,680 ft which occurred as SKW5326 was departing, while ASH5826 was performing a go-around. There were no injuries reported to the 73 passengers and crew onboard the SkyWest airplane or to the 41 passengers and crew members onboard the Mesa airplane. ASH5826 was operating under the provisions of Title 14 Code of Federal Regulations Part 121 as a scheduled domestic passenger flight from Phoenix Sky Harbor International Airport (PHX), Phoenix, Arizona to BUR. SKW5326 was operating under the provisions of Title 14 Code of Federal Regulations Part 121 as a scheduled domestic passenger flight from BUR to San Francisco International Airport (SFO), San Francisco, California.

About 1853, the BUR local control (LC) controller transmitted SKW5326’s callsign to determine if they had switched from ground control frequency to the LC frequency. The crew responded that they were on the frequency. The LC controller then instructed SKW5326 to turn right on runway 33, back taxi if necessary, and line up and wait (LUAW) for runway 33. The crew read back the instructions as issued. According to the Aircraft Performance Study, at the time SKW5326 was provided LUAW instructions, ASH5826 was 7.9 nautical miles (nm) from the threshold, at 2,800 ft above ground level (agl), and approaching runway 33 at BUR.


Figure 1. BUR Airport diagram depicts the location of runway 33, (purple rectangle) and the air traffic control tower (light blue circle).



Figure 2 provides information on the aircraft locations and associated ATC communications for specific times indicated. The Automatic Dependent Surveillance-Broadcast (ADS-B) flight path data for ASH5826 are shown in orange and SKW5326 are noted in blue.


Figure 2. ADS-B flight paths for ASH5826 (orange) and SKW5326 (blue). Selected times and ATC communications are shown.

At 1853:25, the crew of ASH5826 contacted the BUR airport traffic control tower (ATCT) and reported they were on the visual approach to runway 33.

At 1853:36, the LC advised the crew of ASH5826 that traffic, SKW5326, was holding in position on runway 33 and instructed them to continue the approach. The crew read back the instructions as issued.

SKW5326 entered runway 33 about 1853:45, back taxied, and by 1854:30 the airplane had made a 180° turn, aligned with the runway 33 heading, and stopped behind the runway threshold. According to the SKW5326 captain’s statement, they only had performance data for the full length of the runway, so they back taxied to the beginning of runway 33, did a 180-degree turn, and held at the threshold. They were aware that there was an aircraft on approach to runway 33; however, they did not visually acquire the traffic while back taxiing on runway 33. They were in position and held for what seemed to be a couple of minutes.

At 1855:38, the LC cleared SKW5326 for takeoff from runway 33. The crew read back the takeoff clearance for runway 33, as issued. At this time, ASH5826 was 1.6 miles from the threshold and at 500 ft agl.

At 1855:43, the LC cleared ASH5826 to land runway 33. According to the first officer of ASH5826, he contacted the LC again to confirm they were cleared to land, as the LC had just cleared another aircraft for take-off. At 1855:50, SKW5326 began its take-off roll, and then at 1855:53, the LC responded to the crew of ASH5826, “… affirmative, runway 33 cleared to land.”

According to FAA Order 7110.65Z, the controller was required to apply a 6,000 feet separation between a departing aircraft on its takeoff roll and an arriving aircraft on final approach. The NTSB’s aircraft performance study showed that ASH5826 was 1.6 miles from the runway 33 threshold when SKW5326 was cleared for takeoff.

At 1855:55, one of the pilots on ASH5826 asked if SKW5326, was clear of the runway yet, and subsequently, the other pilot of ASH5826 stated, “no he...we’re going around.” According to the flight crew members of ASH5826, they determined the separation was insufficient and initiated a go-around. At this time, SKW5326 was at a groundspeed of 27 kts and accelerating across the runway threshold, and ASH5826 was 4,200 ft from the threshold and at 300 ft agl.

At 1856:00, the LC stated “roger” and then instructed ASH5826 to climb and maintain 4,000 ft, and fly runway heading. The crew of ASH5826 did not respond. The airplanes were 4,000 ft apart at this time. At 1856:14, the crew of ASH5826 asked the LC for the altitude, and the LC stated 4,000 ft. The crew acknowledged and read back 4,000 ft.

At 1856:27, the LC then instructed the ASH5826 to turn right, heading 270°, and subsequently corrected that instruction by stating “left 270°”. The crew acknowledged and readback left 270°. Both airplanes began a left turn once past the runway’s surface. According to the first officer of ASH5826, as they made the turn, he saw SKW5326 climbing underneath them and they received an audible alert from their onboard traffic alert and collision avoidance system (TCAS).

At 1856:57, the LC instructed the crew of SKW5326 to continue on the standard instrument departure route (SID). The crew read back the instructions as issued.

At 1857:02, the LC instructed ASH5826 to continue their climb. The crew read back the instructions as issued.

At 1857:12, according to the Aircraft Performance Study, and as indicated in figure 3, the minimum separation of 1,680 ft horizontally occurred between ASH5826 and SKW5326.



Figure 3. Flight paths for ASH5826 (orange) and SKW5326 (blue) with times and altitudes.

At 1857:14, the LC asked the crew of ASH5826 if they had the Embraer in sight at 2,500 ft off to their right. The crew stated negative and reported that they were responding to and complying with a resolution advisory (RA). The LC controller responded “roger, turn right 30°”, then corrected that instruction and stated, “left 30°”. The crew acknowledged and readback left 30°.

No further relevant ATC communications occurred between the crew of SKW5326 and BUR. ADDITIONAL INFORMATIONTCAS
The manufacturer of the ASH5826 aircraft was contacted and informed the NTSB that the aircraft contained TCAS, Traffic Surveillance System (TSS) model number 4100 and part number 822-2132-001. The system contained data concentrator unit (DCU) part number 822-1310-007. The operator confirmed this information. With this equipment, the manufacturer informed the NTSB that TCAS Vertical Resolution, which includes parameters TCAS Vertical Control, TCAS Combined Control, TCAS Up Advisory and TCAS Down Advisory, did not record data; therefore, these parameters are not provided.

FAA Order JO 7110.65Z, Air Traffic Control

Chapter 1, Section 1, General, paragraph 1–1–1, Purpose of This Order, stated in part:

This order prescribes air traffic control procedures and phraseology for use by persons providing air traffic control services. Controllers are required to be familiar with the provisions of this order that pertain to their operational responsibilities and to exercise their best judgment if they encounter situations that are not covered by it.

Chapter 2, Section 1, paragraph 2-1-1, ATC Service, stated in part:

a. The primary purpose of the ATC system is to prevent a collision involving aircraft operating in the system.
b. In addition to its primary purpose, the ATC system also:
1. Provides a safe, orderly, and expeditious flow of air traffic.
2. Supports National Security and Homeland Defense missions.
c. The ATC system must provide certain additional services to the extent permitted. The provision of additional services is not optional on the part of the controller, but rather required when the work situation permits. It is recognized that the provision of these services may be precluded by various factors, including, but not limited to:
1. Volume of traffic.
2. Frequency congestion.
3. Quality of surveillance.
4. Controller workload.
5. Higher priority duties.
6. The physical inability to scan and detect situations falling in this category

Chapter 2, Section 1, paragraph 2-1-2 Duty Priority, stated in part:

a. Give first priority to separating aircraft and issuing safety alerts as required in this order. Good judgment must be used in prioritizing all other provisions of this order based on the requirements of the situation at hand.

NOTE- Because there are many variables involved, it is virtually impossible to develop a standard list of duty priorities that would apply uniformly to every conceivable situation. Each set of circumstances must be evaluated on its own merit, and when more than one action is required, controllers must exercise their best judgment based on the facts and circumstances known to them. That action which is most critical from a safety standpoint is performed first.

Chapter 2, section 1, paragraph 2-1-6, Safety Alert, stated in part:

Issue a safety alert to an aircraft if you are aware the aircraft is in a position/altitude that, in your judgment, places it in unsafe proximity to terrain, obstructions, or other aircraft. Once the pilot informs you action is being taken to resolve the situation, you may discontinue the issuance of further alerts. Do not assume that because someone else has responsibility for the aircraft that the unsafe situation has been observed and the safety alert issued; inform the appropriate controller.

NOTE- 1. The issuance of a safety alert is a first priority (see paragraph 2-1-2, Duty Priority) once the controller observes and recognizes a situation of unsafe aircraft proximity to terrain, obstacles, or other aircraft. Conditions, such as workload, traffic volume, the quality/limitations of the radar system, and the available lead time to react are factors in determining whether it is reasonable for the controller to observe and recognize such situations. While a controller cannot see immediately the development of every situation where a safety alert must be issued, the controller must remain vigilant for such situations and issue a safety alert when the situation is recognized.

Chapter 3, section 1, paragraph 3-3-12, Visually Scanning Runways, stated in part:

a. Local controllers must visually scan runways to the maximum extent possible.

b. Ground control must assist local control in visually scanning runways, especially when runways are in close proximity to other movement areas.

Chapter 3, section 9, paragraph 3-9-4, Line Up and Wait (LUAW), stated in part:

a. The intent of LUAW is to position aircraft for an imminent departure. Authorize an aircraft to line up and wait, except as restricted in subparagraph g, when takeoff clearances cannot be issued because of traffic. Issue traffic information to any aircraft so authorized. Traffic information may be omitted when the traffic is another aircraft which has landed on or is taking off the runway and is clearly visible to the holding aircraft. Do not use conditional phrases such as “behind landing traffic” or “after the departing aircraft.”

b. First state the runway number followed by the line up and wait clearance. PHRASEOLOGY-RUNWAY (number), LINE UP AND WAIT.

NOTE- When using LUAW, an imminent departure is one that will not be delayed beyond the time that is required to ensure a safe operation. An aircraft should not be in LUAW status for more than 90 seconds without additional instructions.

Chapter 3, Section 10, paragraph 3-10-3, Same Runway Separation, stated in part:

a. Separate an arriving aircraft from another aircraft using the same runway by ensuring that the arriving aircraft does not cross the landing threshold until one of the following conditions exists or unless authorized in paragraph 3-10-10, Altitude Restricted Low Approach.

2. The other aircraft has departed and crossed the runway end. (See FIG 3-10-4). If you can determine distances by reference to suitable landmarks and the other aircraft is airborne, it need not have crossed the runway end if the following minimum distance from the landing threshold exists:
(a) Category I aircraft landing behind Category I or II- 3,000 feet.
(b) Category II aircraft landing behind Category I or II- 4,500 feet.
(c) When either is a category III aircraft-6,000 feet.

Paragraph 5-8-4 of the order, Departure and Arrival, stated that controllers are to “separate a departing aircraft from an arriving aircraft on final approach by a minimum of 2 miles if separation will increase to a minimum of 3 miles (5 miles when 40 miles or more from the radar antenna) within 1 minute after takeoff.”

Paragraph 5-8-4 also noted the following:
1. This procedure permits a departing aircraft to be released so long as an arriving aircraft is no closer than 2 miles from the runway at the time. This separation is determined at the time the departing aircraft commences takeoff roll.

FAA Order JO 7110.65Z was superseded by JO 7110.65BB on February 20, 2025, but did not change the above information. FLIGHT RECORDERSBoth airplanes were equipped with Flight Data Recorders (FDRs) and Cockpit Voice Recorders (CVRs). The FDR data was obtained for both airplanes, but the incident was overwritten on both airplanes’ two-hour CVRs.

The FDR recorded airplane flight information in a digital format using solid-state flash memory as the recording medium. FDRs receive data in the ARINC 573/717/747 configurations and are required to record a minimum of 25 hours of flight data. FDRs are configured to record a set number of 12-bit words of digital information every second.

The NTSB Vehicle Recorder Division received a L-3/Fairchild FA2100 FDR having part number 2100-2045-22 and serial number 00904855 from Mesa Airlines. Additionally, an electronic file containing the FDR data was received from SkyWest Airlines.

The L-3/Fairchild FA2100 FDR (ASH5826) was configured to record 512 12-bit words of digital information every second and was designed to meet the crash-survivability requirements of TSO-C124b. The FDR was in good condition and the data were extracted normally from the recorder using instructions provided by the recorder manufacturer. The FDR recording contained approximately 154.9 hours of data. The incident flight was the eighth to last flight of the recording, and its duration was approximately 1 hour and 25 minutes. The parameters evaluated for the purpose of this report appeared to be in accordance with federal FDR carriage requirements.

The FDR file obtained from SKW5326 was configured to record 512 12-bit words of digital information every second. The FDR recording contained approximately 140.8 hours of data. The incident flight was the third to last flight of the recording, and its duration was approximately 1 hour and 17 minutes. The parameters evaluated for the purpose of this report appeared to be in accordance with federal FDR carriage requirements.

The latitude and longitude parameters on the FDRs of both airplanes were not recorded with enough precision to accurately determine the airplanes’ locations. Therefore, Automatic Dependent Surveillance-Broadcast (ADS-B) data provided by the FAA was used for the airplanes’ locations. ADS-B broadcasts an airplane’s Global Positioning System (GPS) position and other data to the ground where it is recorded. The GPS position has an accuracy of approximately 20 meters (65 ft) in both the horizontal and vertical dimensions.

However, ADS-B data for SKW5326 was not recorded until the airplane had begun its take-off roll. Its location during taxi was determined using the less accurate FDR data.