April 15, 1996

Mission Summary

DC-8 SUCCESS flight #203 (scientist: Eric Jensen)

SUMMARY: The basic flight went very well. All of the instruments are functioning, with mainly small problems left to be worked out. We met all of our major objectives, testing instruments, calibrating the MMS and coordinating flight maneuvers with the T-39 and the ER-2.

Mission Objective

DC-8 TEST-FLIGHT

• practice coordinated flight maneuvers for DC-8 and T-39
• attempt a coordinated overpass of the ER-2 and DC-8/T-39
• test the Valero radiaometers on the ER-2, third test-flight
• evaluate how long after takeoff the DC-8 instruments become operational
• repeat a few of the calibration maneuvers for the MMS system

Flight Track

Flight Log

OPERATIONS
FLIGHT PLAN:
Planned takeoff: 17.00 UTC (12.00 local time)
The DC-8 and T-39 will climb out in formation and head to the CART site. Over the CART site racetrack patterns will be flown aligned with the wind (predicted to be 330 deg.). The DC-8 and T-39 will practice following one another. If possible, the DC-8 and T-39 will coordinate with the ER-2 to pass over a particular waypoint simultaneously. The success of the coordinated overpass will be determined visually by the ER-2 pilot. At the end of the flight, we will fly maneuvers to calibrate MMS.

TAKEOFF/LANDING
The DC-8 left Salina at 17.00 UTC (12.00 am local time) and returned to Salina at 20.30 UTC

FLIGHT REPORT
Circled over KSLP then headed south to WP 2. Climbed through stratocu at about 3-5 K'. Lost power to systems on converter 1, possibly due to short in 3-stage hygrometer pump. Climbed to 31 K'. T-39 flew off right wingtip, then flew in front. No coning. Tropopause Temp about -50 C. Indications from Twohey and DeMott/Rogers that we were intersecting plume: 60 s of enhanced CN number density with numbers as high as about 15000/cc. Most of the CN were involatile based on Twohey's heated inlet measurements. T-39 about 0.75 miles ahead. T-39 exhaust was also detected in H2O and CO2 measurements. Next, the T-39 pulled in behind and stayed behind. When T-39 used radar, MTP was fouled. Short contrail was observed during a few brief periods by T-39 while following. Laid contrail over CART site at T of about -50 C, low RHI. This contrail was not visible on video or looking back. Didn't begin racetrack over CART site until about 1.5 hours into flight. Air traffic problems forced turn in first leg of racetrack. T-39 headed home after waypoint 5 was reached. Started coning visibly at -53 C, 30% RHI. Descended to 25 K' to do MMS maneuvers. Did box and yaw maneuvers at 25 K'. Did pitch maneuvers at 23 K'. Attempted to repeat pattern at 17 K'. Air traffic forced one leg of box to be a couple of minutes. Yaw maneuver at 17K', and pitch maneuver at 16K'.

METEOROLOGY-REPORT
FORECAST: No clouds, tropopause too warm for even transient contrails.
OBSERVATIONS: As expected, tropopause was low and warm: near 10 km and -50 C. Popcorn cumulous was present at about 3-5 K'.

INSTRUMENT STATUS
All instruments are functioning.

• BALLENTHIN: No problems
• BAUMGARDNER: No major problems. Minor datasystem problems.
• BRUNE: ATHOS functioned well. Added NO and got good HO2 signal. Still need improved sensitivity. Need a few down days soon.
• CHAN: No problems. Expect to need some maeuvers every flight.
• COGGIOLA: No problems
• COOPER: Water dripped on instrument, but no major problem.
• DADS: Fine. Lost data in power failure.
• FERRY: Worked fine.
• GARY: Worked except maybe when T-39 radar was on.
• GERBER: Temperature, airspeed - dependent offset discovered.
• HAGEN: Worked OK.
• HALLET: Replicator worked, no clouds.
• HEYMSFIELD: VIPS and 2D-C, worked well.
• HUDSON: Pump failed near end of flight. Need replacement.
• LAWSON: Not on board
• RODGERS: Good data
• SACHSE: Hygrometer worked well. Alignment problem with CO instrument.
• TALBOT: No problems
• TWOHY: Good shape
• UTHE: Lidar worked well. Still adjusting displays.
• VALERO: Worked well. One chanel on TDDR still down.
• WEINHEIMER: Everything fine

Mission Highlights

• strong east-west O3 gradient observed near CART site
• T-39 plume was observed with high CN (up to 10000/cc, mostly involatile) and in CO2 and H2O measurements.
• background CN number densities were about 150 - 200/cc with about 50-80% non-volatile.