NTSB公佈華府撞機事件調查最新進展 #大紀元新聞網

Summary

The investigation into a midair collision near Reagan National Airport on January 29th has concluded the on-scene phase. A Blackhawk helicopter was undergoing a check ride when it collided with a CRJ jet. The Blackhawk crew, possibly wearing night vision goggles, did not receive certain ATC communications due to transmission interference, which could have impacted their awareness of the jet’s position. The investigation is ongoing, with a focus on determining discrepancies in altitude readings, visibility, and equipment malfunctions. The NTSB is conducting a thorough review, including a visibility study and examining wreckage to clarify the factors contributing to the collision.

Takeaways

• 😀 The investigation into the midair collision near Reagan National Airport has concluded its on-scene phase, and the perishable evidence has been gathered.
• 😀 The Blackhawk flight was a combined annual and night vision goggle check ride, a practical exam for the pilot's qualifications.
• 😀 The helicopter's route followed FAA-designated helicopter routes, with varying altitude limits based on locations near landmarks like the Key Bridge and Memorial Bridge.
• 😀 Preliminary findings show that at 8:30 PM, the Blackhawk began descending from 1,000 feet, traveling southbound near Leonville, Maryland.
• 😀 The CRJ was cleared for a visual approach to Runway 1, and both aircraft were in communication with DCA Tower as they neared the airport.
• 😀 The Blackhawk crew experienced communication issues with ATC, including missed transmissions and interruptions while requesting visual separation from the CRJ.
• 😀 At 8:47:39, a radio transmission from the tower instructed the Blackhawk crew to pass behind the CRJ, but this message may not have been fully received due to the interference from the Blackhawk’s mic keying.
• 😀 At the time of the collision, the CRJ was descending at a rate of 448 feet per minute, and the Blackhawk was at a steady 278 feet altitude based on radio altitude data.
• 😀 The NTSB is investigating potential discrepancies in the Blackhawk’s altitude readings, particularly the accuracy of the barometric altimeter and how it compares to the FDR’s radio altitude data.
• 😀 The NTSB will conduct a visibility study involving laser scans of both the CRJ and Blackhawk cockpits to evaluate what each pilot could have seen during the flight, considering the possible use of night vision goggles.
• 😀 The investigation has identified that the Blackhawk was equipped with ADS-B Out, but it was not transmitting; the cause of this issue is still under investigation, including whether the equipment was malfunctioning or turned off.

Q & A

What was the main purpose of the Blackhawk flight mentioned in the transcript?

The Blackhawk flight was a check ride, which is a practical exam for a pilot to qualify for specific air crew or mission duties. In this case, it was a combined annual and night vision goggle check ride.

What is the significance of the night vision goggles in the Blackhawk flight?

The crew was likely wearing night vision goggles throughout the flight, as suggested by the nature of the flight. If they were removed, the crew was required to discuss operating 'unaided', but no such discussion was found on the cockpit voice recorder (CVR).

What role did air traffic control (ATC) play in the sequence leading to the midair collision?

ATC played a key role in managing the aircraft's routes, providing clearances, and issuing instructions to ensure safe separation. However, there were communication issues, such as the Blackhawk not receiving some transmissions from ATC due to interference and mic keying.

What was the issue with the Blackhawk's altitude readings during the flight?

There were discrepancies in the Blackhawk's altitude data. The flight data recorder (FDR) recorded a radio altitude of 278 feet at the time of the collision, but this may not match the actual altitude seen by the crew on their barometric altimeters. The NTSB is investigating this discrepancy.

How are the NTSB investigators working to understand the altitude discrepancies in the Blackhawk flight?

The NTSB is working with Sikorsky, Collins Aviation, and the Army to retrieve engineering documentation and assess how this might have affected other systems. They will also examine the wreckage, including the air data systems and altimeters, to determine the altitude the pilots saw.

What challenges do investigators face when determining the altitude the Blackhawk crew saw during the flight?

Investigators face several challenges, including the fact that the FDR recorded bad pressure altitude data and the barometric pressure setting was not recorded. This means that other methods, like examining the wreckage and working with the helicopter's engineering systems, must be used.

Was there an issue with the Blackhawk's ADS-B system, and what is being investigated?

Yes, the Blackhawk was equipped with ADS-B out, which is meant to transmit the helicopter's position. However, it was not transmitting, and the investigation will look into whether there was an equipment malfunction, improper installation, or if the ADS-B was turned off.

What is the purpose of the visibility study being conducted by the NTSB?

The visibility study will examine what the Blackhawk crew could and could not see during the flight, considering factors such as night vision goggles, cockpit seating positions, and other variables. This will help understand how visibility may have contributed to the collision.

Why were helicopter flights restricted around the area after the collision, and is this restriction permanent?

The immediate restriction on helicopter flights, except for life-saving and presidential flights, was a precautionary safety measure taken by the Secretary of Transportation. It's too early to determine if a permanent restriction is necessary, as the investigation is ongoing.

How does the NTSB typically handle urgent safety recommendations during an investigation?

The NTSB does not wait until the end of the investigation to issue urgent safety recommendations. If a safety deficiency is identified that requires immediate action, the NTSB can issue a recommendation at any point during the investigation.