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Flight crew of MD80 departing sjc via sjc departure procedure encounter erratic DME indications from sjc VOR.
| Attributes | |
| ACN | 595505 |
| Time | |
| Date | 200310 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : sjc.vor |
| State Reference | CA |
| Aircraft 1 | |
| Controlling Facilities | tracon : nct.tracon tower : sjc.tower |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Series (DC-9-80) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure sid : sjc |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 595505 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| ASRS Report | 595494 |
| Events | |
| Anomaly | non adherence : published procedure other spatial deviation |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem flight crew : returned to intended or assigned course |
| Supplementary | |
| Problem Areas | Aircraft Navigational Facility Flight Crew Human Performance |
| Primary Problem | Navigational Facility |
| Situations | |
| Navigational Aid | SJC.VOR |
Narrative:
Taking off runway 30L sjc, SJC9 departure. At liftoff, DME showed 1.8 DME and holding steady. DME then increased to 2.3. Then DME counted down to 2.2. At this point, DME appeared unreliable, so I started turn to 110 degrees to intercept oak 121 degree radial. Supplemental information from acn 595494: after liftoff, I raised the landing gear and commenced post takeoff checklist and maintained outside visual lookout. About 30-40 seconds after liftoff, I noticed VOR #1 readout of 1.5 DME. About 15-20 seconds later, the captain began verbally questioning the sjc DME readout. I noticed the DME on my display to read 2.2 DME and increasing normally. I dialed in the new heading on the course select and said that we had passed the turn point. I was not watching the DME readout constantly like the captain due to my PNF duties.
Original NASA ASRS Text
Title: FLT CREW OF MD80 DEPARTING SJC VIA SJC DEP PROC ENCOUNTER ERRATIC DME INDICATIONS FROM SJC VOR.
Narrative: TAKING OFF RWY 30L SJC, SJC9 DEP. AT LIFTOFF, DME SHOWED 1.8 DME AND HOLDING STEADY. DME THEN INCREASED TO 2.3. THEN DME COUNTED DOWN TO 2.2. AT THIS POINT, DME APPEARED UNRELIABLE, SO I STARTED TURN TO 110 DEGS TO INTERCEPT OAK 121 DEG RADIAL. SUPPLEMENTAL INFO FROM ACN 595494: AFTER LIFTOFF, I RAISED THE LNDG GEAR AND COMMENCED POST TKOF CHKLIST AND MAINTAINED OUTSIDE VISUAL LOOKOUT. ABOUT 30-40 SECONDS AFTER LIFTOFF, I NOTICED VOR #1 READOUT OF 1.5 DME. ABOUT 15-20 SECONDS LATER, THE CAPT BEGAN VERBALLY QUESTIONING THE SJC DME READOUT. I NOTICED THE DME ON MY DISPLAY TO READ 2.2 DME AND INCREASING NORMALLY. I DIALED IN THE NEW HDG ON THE COURSE SELECT AND SAID THAT WE HAD PASSED THE TURN POINT. I WAS NOT WATCHING THE DME READOUT CONSTANTLY LIKE THE CAPT DUE TO MY PNF DUTIES.
Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.