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Medium large transport descended through altitude of company medium large transport while holding at farmm intersection. Controller started to make same mistake and flight crew corrected him.
| Attributes | |
| ACN | 95092 |
| Time | |
| Date | 198809 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : jvl airport : ord |
| State Reference | WI |
| Altitude | msl bound lower : 13000 msl bound upper : 13000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : mdw |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport |
| Flight Phase | descent other other |
| Route In Use | enroute airway : ord |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport |
| Flight Phase | other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 450 flight time total : 22000 |
| ASRS Report | 95092 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | other flight crewa |
| Resolutory Action | none taken : anomaly accepted |
| Consequence | Other |
| Miss Distance | horizontal : 6000 vertical : 0 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
We first became aware of a problem when we were holding at farmm intersection at an altitude of 11000' and being controled by ord approach control on 125.7. Company flight abc was cleared from 13000' to 10000'. We were at 11000' and this fact was told to approach control by our company flight abc. He was then told to maintain 13000'. Thinking back to the time we entered the hold, we remember the fact that company was below us but he now was above us. Possibly we were descended through his altitude when we were cleared to descend to 11000' from 14000'. We were also asked at that time to check each altitude as we passed them. This we did accompanied with the appropriate flight number. It was later verified with the other pilot that we did pass through their altitude at 13000' because they visually watched us descend right off their nose within a mile or so. They tried to warn approach of the problem but were told to stand by. Evidently they had lots of problems.
Original NASA ASRS Text
Title: MLG DESCENDED THROUGH ALT OF COMPANY MLG WHILE HOLDING AT FARMM INTERSECTION. CTLR STARTED TO MAKE SAME MISTAKE AND FLT CREW CORRECTED HIM.
Narrative: WE FIRST BECAME AWARE OF A PROB WHEN WE WERE HOLDING AT FARMM INTXN AT AN ALT OF 11000' AND BEING CTLED BY ORD APCH CTL ON 125.7. COMPANY FLT ABC WAS CLRED FROM 13000' TO 10000'. WE WERE AT 11000' AND THIS FACT WAS TOLD TO APCH CTL BY OUR COMPANY FLT ABC. HE WAS THEN TOLD TO MAINTAIN 13000'. THINKING BACK TO THE TIME WE ENTERED THE HOLD, WE REMEMBER THE FACT THAT COMPANY WAS BELOW US BUT HE NOW WAS ABOVE US. POSSIBLY WE WERE DSNDED THROUGH HIS ALT WHEN WE WERE CLRED TO DSND TO 11000' FROM 14000'. WE WERE ALSO ASKED AT THAT TIME TO CHK EACH ALT AS WE PASSED THEM. THIS WE DID ACCOMPANIED WITH THE APPROPRIATE FLT NUMBER. IT WAS LATER VERIFIED WITH THE OTHER PLT THAT WE DID PASS THROUGH THEIR ALT AT 13000' BECAUSE THEY VISUALLY WATCHED US DSND RIGHT OFF THEIR NOSE WITHIN A MILE OR SO. THEY TRIED TO WARN APCH OF THE PROB BUT WERE TOLD TO STAND BY. EVIDENTLY THEY HAD LOTS OF PROBS.
Data retrieved from NASA's ASRS site as of August 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.