 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Atx mdt overshoots assigned altitude in descent due turbulence and downdraft, deviates from assigned heading.
| Attributes | |
| ACN | 134895 |
| Time | |
| Date | 199001 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : den |
| State Reference | CO |
| Altitude | msl bound lower : 10300 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : den |
| Operator | common carrier : air taxi |
| Make Model Name | Medium Transport |
| Navigation In Use | Other |
| Flight Phase | descent : approach descent other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air taxi |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 12000 flight time type : 1200 |
| ASRS Report | 134895 |
| Person 2 | |
| Affiliation | company : air taxi |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | altitude deviation : overshoot conflict : airborne less severe inflight encounter : weather other spatial deviation |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
We were cleared to descend to 11000' on the den 213 degree right into den area. There were sigmets for moderate to severe turbulence and strong up and downdrafts along the mountains in the den area. Upon reaching 11000' we started a level off, but the downdraft we were in prevented us from stopping our descent at 11000'. We had maximum power and pitched up to 10 degrees, but continued to descend to about 10300' before recovering. We were turning to a heading of 350 degrees when the approach controller asked us our altitude. We replied with our altitude. He asked if we were descending to that altitude. We told him we were in a downdraft. He replied. With 'we need you at 11000', you have traffic at 10000' at your 10-11 O'clock position.' we were starting a slow climb to 11000' at that time, as we had managed to stop the altitude loss. During the recovery we were assigned heading of FL350. I understood the heading as 050 degrees. The turn was for traffic that was overtaking us from the 6 O'clock position. The frequency was extremely busy, almost non-stop talk. It was several seconds before the controller questioned our heading. When he did, he just asked what heading we were flying. West told him 050 degrees. He then said 'I need you on a 350 degree heading for traffic.' during this time we were still trying to recover from the downdraft. It was not until we were on the 350 degree heading that the controller questioned our altitude. It is my understanding that an altitude deviation showed up on the controller's equipment well before 700'. With the frequency congestion, and working very hard to stop the altitude loss, we were unable to report our altitude problems. We were 700' low before the controller became aware of our altitude. I feel we could have coordinated with ATC on our problem if the frequencys were not as busy during a critical phase of flight. During periods of strong up and downdrafts and wind shear, maybe we should do the same. Altitude sep is sometimes in jeopardy in these situations and at no fault of the flight crews and controllers.
Original NASA ASRS Text
Title: ATX MDT OVERSHOOTS ASSIGNED ALT IN DESCENT DUE TURBULENCE AND DOWNDRAFT, DEVIATES FROM ASSIGNED HEADING.
Narrative: WE WERE CLRED TO DSND TO 11000' ON THE DEN 213 DEG R INTO DEN AREA. THERE WERE SIGMETS FOR MODERATE TO SEVERE TURB AND STRONG UP AND DOWNDRAFTS ALONG THE MOUNTAINS IN THE DEN AREA. UPON REACHING 11000' WE STARTED A LEVEL OFF, BUT THE DOWNDRAFT WE WERE IN PREVENTED US FROM STOPPING OUR DSCNT AT 11000'. WE HAD MAX PWR AND PITCHED UP TO 10 DEGS, BUT CONTINUED TO DSND TO ABOUT 10300' BEFORE RECOVERING. WE WERE TURNING TO A HDG OF 350 DEGS WHEN THE APCH CTLR ASKED US OUR ALT. WE REPLIED WITH OUR ALT. HE ASKED IF WE WERE DSNDING TO THAT ALT. WE TOLD HIM WE WERE IN A DOWNDRAFT. HE REPLIED. WITH 'WE NEED YOU AT 11000', YOU HAVE TFC AT 10000' AT YOUR 10-11 O'CLOCK POS.' WE WERE STARTING A SLOW CLB TO 11000' AT THAT TIME, AS WE HAD MANAGED TO STOP THE ALT LOSS. DURING THE RECOVERY WE WERE ASSIGNED HDG OF FL350. I UNDERSTOOD THE HDG AS 050 DEGS. THE TURN WAS FOR TFC THAT WAS OVERTAKING US FROM THE 6 O'CLOCK POS. THE FREQ WAS EXTREMELY BUSY, ALMOST NON-STOP TALK. IT WAS SEVERAL SECS BEFORE THE CTLR QUESTIONED OUR HDG. WHEN HE DID, HE JUST ASKED WHAT HDG WE WERE FLYING. W TOLD HIM 050 DEGS. HE THEN SAID 'I NEED YOU ON A 350 DEG HDG FOR TFC.' DURING THIS TIME WE WERE STILL TRYING TO RECOVER FROM THE DOWNDRAFT. IT WAS NOT UNTIL WE WERE ON THE 350 DEG HDG THAT THE CTLR QUESTIONED OUR ALT. IT IS MY UNDERSTANDING THAT AN ALT DEVIATION SHOWED UP ON THE CTLR'S EQUIP WELL BEFORE 700'. WITH THE FREQ CONGESTION, AND WORKING VERY HARD TO STOP THE ALT LOSS, WE WERE UNABLE TO RPT OUR ALT PROBS. WE WERE 700' LOW BEFORE THE CTLR BECAME AWARE OF OUR ALT. I FEEL WE COULD HAVE COORDINATED WITH ATC ON OUR PROB IF THE FREQS WERE NOT AS BUSY DURING A CRITICAL PHASE OF FLT. DURING PERIODS OF STRONG UP AND DOWNDRAFTS AND WIND SHEAR, MAYBE WE SHOULD DO THE SAME. ALT SEP IS SOMETIMES IN JEOPARDY IN THESE SITUATIONS AND AT NO FAULT OF THE FLT CREWS AND CTLRS.
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.