In the media - WaPo 1/30 "Helicopters flying along Potomac frequently pose dangers to passenger jets”… "On Tuesday night, just 24 hours before a deadly collision between a military helicopter and a regional jet at Reagan National Airport, a different passenger jet coming in for a landing at the airport alerted the tower it had to abort. The reason: risk of possible collision with a helicopter. A similar situation played out less than a week earlier, on Jan. 23, when a flight from Charlotte suddenly pulled out of its approach at National. The captain informed passengers that he was tracking a helicopter and needed to abort the landing.”(the "Tuesday night" event of 1/28 was the RPA4514/PAT11 go-around @4mi final with ~1000ft separation, covered here -
https://forums.liveatc.net/atcaviation-audio-clips/kdca-12825-2000pm-rpa4514-pat11-go-around/)
What happened on 1/23?
- At approx 23:22Z / 18:22ET - AAL1564 approx 2 miles from DCA, previously cleared to land for Rwy 19, receives an advisory from the Tower "on TCAS quarter of a mile towards your left is a helicopter has you in sight maintaining visual separation. In event of a missed approach prepare to go to the West".
- This helicopter was an Air Force Huey c/s MUSEL-7 that had lifted ~2mins prior from South Cap helipad on the Anacostia River in DC, low-level in the opposite direction up the Washington Channel to the East of the Potomac, intending to transition to VA which crosses the river under the Rwy 19 corridor just South of Memorial Bridge (200ft ceiling, passing behind any traffic on final).
- Note - Earlier viz-sep to MUSEL-7 and advisory to AAL1564 were also provided - but the audio is unclear and no acknowledgement is audible from AAL1564.
- Approx 45 seconds later after acknowledging the 2mi advisory with "Prepare for the West", AAL1564 called go-around, passing over Rwy 19 and executing turn and climb to the West towards the departure end. See ADBS-Ex screenshot overlaid with assumed/approximate course of MUSEL-7 (no tracking available).
- AAL2959 also departed immediately ahead of AAL1564 but no indication this was a factor. There was no conversation about the helicopter with Tower or Ground upon final landing at 23:31Z.
Note here there were separate controllers on HELI and TWR frequencies (as well as controller changes on TWR thru this timeframe). In this situation, aircraft only hear the controller on their frequency, so fixed wing is not hearing helicopter clearances and advisories from the Tower, and vice versa. On 1/29 collision, there was a single controller on both frequencies and the Tower side of all communications was audible on both frequencies.
Times below and on the picture are based on LiveATC feed timing which may not be exactly in sync with ADSB data, locations are approximate.
Attached recording is in real-time from 23:18:30 - 23:23:20Z, merge of TWR and HELI and unedited for other traffic other than noise removal.
Timeline (Z)23:18:45
AAL1564 Boeing 737 cleared to land Rwy 19, advised of departing traffic (Controller #1 on TWR)
23:20:00
Air Force UH-1N Twin Huey from 1st Helicopter Squadron out of Andrews, c/s MUSEL-7 lifting South Cap helipad is approved for "Route 1 - Pentagon Transition - Zone 5" (Controller #2 on HELI - separate from TWR)
This route is a transition from DC to VA across the river just South of the Memorial Bridge to Zone 5, which crosses under the arrival corridor for Rwy 19 approx 2 miles North of DCA with 200ft ceiling
MUSEL-7 ultimate destination was Inova Hospital in Fairfax which is a routine destination, nothing to indicate this was medevac.23:20:40
HELI/MUSEL-7 visual separation of "American 7 [inaudible]... descending for the field", reports traffic in sight (Controller #2 on HELI)
TWR/AAL1564 advised of "opposite direction ... has you in sight" - [some parts inaudible - no response audible on the LiveATC feed] (Controller #3 on TWR)
23:21:45
TWR/AAL2959 - "AAL2959 your company is on a 2 mile final descending rapidly, no delay Rwy 1-9er clear for take off" (Controller #4 on TWR, remains)
23:21:55
TWR/AAL1564 given advisory by Tower for helo traffic - "
on TCAS quarter of a mile towards your left is a helicopter has you in sight maintaining visual separation. In event of a missed approach prepare to go to the West"
AAL1564 reads back "Prepare for the West / American 1564"
At this point MUSEL-7 would have been somewhere in the Washington Channel / Tidal Basin area; AAL1564 somewhere around Theodore Roosevelt Bridge, just North of Memorial Bridge23:22:32
MUSEL-7 reports Memorial (passing behind AAL1564)
23:22:42
AAL1564 calls go-around, given 250 heading to 3000ft. Switches to Potomac departure 118.95. Landed 23:31Z.
