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MD88 flight crew climbs 1000 ft above their assigned altitude of FL280 when the pilots dial in 28 pt 92 versus 29 pt 92 on their altimeters. The bos altimeter setting had been 28 pt 87.
| Attributes | |
| ACN | 390012 |
| Time | |
| Date | 199712 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : baf |
| State Reference | CT |
| Altitude | msl bound lower : 28000 msl bound upper : 29000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zbw tower : pit |
| Operator | common carrier : air carrier |
| Make Model Name | MD-88 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude cruise other |
| Route In Use | enroute airway : j77 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 7500 flight time type : 1500 |
| ASRS Report | 390012 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 180 flight time total : 15000 flight time type : 3500 |
| ASRS Report | 389820 |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | flight crew : returned to assigned altitude other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
After leveloff at FL280, center queried us about our altitude. We responded that all 3 altimeters were indicating FL280. Center responded that mode C indicated FL290. We then discovered that our altimeters were set at 28.92 rather than 29.92. The departure altitude setting at bos was 28.87. At transition altitude both pilots inadvertently set 28.92. A contributing factor was the very low altimeter setting and not used to such drastic changes. Additionally, when the cockpit instrument lights are set at very dim levels, it is very difficult to differentiate between 29.92 and 28.82.
Original NASA ASRS Text
Title: MD88 FLC CLBS 1000 FT ABOVE THEIR ASSIGNED ALT OF FL280 WHEN THE PLTS DIAL IN 28 PT 92 VERSUS 29 PT 92 ON THEIR ALTIMETERS. THE BOS ALTIMETER SETTING HAD BEEN 28 PT 87.
Narrative: AFTER LEVELOFF AT FL280, CTR QUERIED US ABOUT OUR ALT. WE RESPONDED THAT ALL 3 ALTIMETERS WERE INDICATING FL280. CTR RESPONDED THAT MODE C INDICATED FL290. WE THEN DISCOVERED THAT OUR ALTIMETERS WERE SET AT 28.92 RATHER THAN 29.92. THE DEP ALT SETTING AT BOS WAS 28.87. AT TRANSITION ALT BOTH PLTS INADVERTENTLY SET 28.92. A CONTRIBUTING FACTOR WAS THE VERY LOW ALTIMETER SETTING AND NOT USED TO SUCH DRASTIC CHANGES. ADDITIONALLY, WHEN THE COCKPIT INST LIGHTS ARE SET AT VERY DIM LEVELS, IT IS VERY DIFFICULT TO DIFFERENTIATE BTWN 29.92 AND 28.82.
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.