 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
MD88 flight crew has compass deflection after takeoff leading to a heading error. Suspect passenger electronic device problem with passenger who turned on his computer.
| Attributes | |
| ACN | 419231 |
| Time | |
| Date | 199811 |
| Day | Wed |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : ord airport : ord |
| State Reference | IL |
| Altitude | msl bound lower : 5000 msl bound upper : 5000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : ord |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 30 flight time total : 10000 |
| ASRS Report | 419231 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other other spatial deviation |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : became reoriented flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Air Traffic Incident | other |
Narrative:
Departing ord on a heading of 180 degrees at 5000 ft and 250 KTS, autoplt on, both compass system started a r-hand turn indicating 180 degree heading to be further to the right from our existing heading and drifting right. Autoplt continued to follow drifting heading to the right. A quick look at our VOR indicated proper course to actually be to the left. (Since both heading system gave same indications and come from independent sources, it was very difficult to assess what system was malfunctioning.) we had no abnormal warning indications to verify if/which system was giving bad information. Right turn continued at a very rapid rate to about 60 degrees to the right of intended heading before we initiated a turn back to the left. ATC verified that we were significantly off heading. We re- established on course using raw VOR data but heading was still off by 30-40 degrees. Heading slowly recovered to normal over about 20 mins. No cause for the malfunction was found in the cockpit. We speculated that we may have had some sort of external interference since both system were affected. After questioning a passenger admitted that he turned on his computer just after takeoff and prior to the seat belt sign being turned off. We suspect that this may have been the cause of the malfunction. The slow recovery of the heading system is a system limitation.
Original NASA ASRS Text
Title: MD88 FLC HAS COMPASS DEFLECTION AFTER TKOF LEADING TO A HDG ERROR. SUSPECT PAX ELECTRONIC DEVICE PROB WITH PAX WHO TURNED ON HIS COMPUTER.
Narrative: DEPARTING ORD ON A HDG OF 180 DEGS AT 5000 FT AND 250 KTS, AUTOPLT ON, BOTH COMPASS SYS STARTED A R-HAND TURN INDICATING 180 DEG HDG TO BE FURTHER TO THE R FROM OUR EXISTING HDG AND DRIFTING R. AUTOPLT CONTINUED TO FOLLOW DRIFTING HDG TO THE R. A QUICK LOOK AT OUR VOR INDICATED PROPER COURSE TO ACTUALLY BE TO THE L. (SINCE BOTH HDG SYS GAVE SAME INDICATIONS AND COME FROM INDEPENDENT SOURCES, IT WAS VERY DIFFICULT TO ASSESS WHAT SYS WAS MALFUNCTIONING.) WE HAD NO ABNORMAL WARNING INDICATIONS TO VERIFY IF/WHICH SYS WAS GIVING BAD INFO. R TURN CONTINUED AT A VERY RAPID RATE TO ABOUT 60 DEGS TO THE R OF INTENDED HDG BEFORE WE INITIATED A TURN BACK TO THE L. ATC VERIFIED THAT WE WERE SIGNIFICANTLY OFF HDG. WE RE- ESTABLISHED ON COURSE USING RAW VOR DATA BUT HDG WAS STILL OFF BY 30-40 DEGS. HDG SLOWLY RECOVERED TO NORMAL OVER ABOUT 20 MINS. NO CAUSE FOR THE MALFUNCTION WAS FOUND IN THE COCKPIT. WE SPECULATED THAT WE MAY HAVE HAD SOME SORT OF EXTERNAL INTERFERENCE SINCE BOTH SYS WERE AFFECTED. AFTER QUESTIONING A PAX ADMITTED THAT HE TURNED ON HIS COMPUTER JUST AFTER TKOF AND PRIOR TO THE SEAT BELT SIGN BEING TURNED OFF. WE SUSPECT THAT THIS MAY HAVE BEEN THE CAUSE OF THE MALFUNCTION. THE SLOW RECOVERY OF THE HDG SYS IS A SYS LIMITATION.
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.