|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : evw|
|Altitude||msl bound lower : 8600|
msl bound upper : 9300
|Controlling Facilities||artcc : zlc|
|Operator||general aviation : corporate|
|Make Model Name||Small Transport, Low Wing, 2 Turboprop Eng|
|Flight Phase||cruise other|
descent : approach
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Experience||flight time last 90 days : 90|
flight time total : 8000
|Function||flight crew : first officer|
|Qualification||pilot : atp|
|Anomaly||altitude deviation : excursion from assigned altitude|
inflight encounter : weather
non adherence : published procedure
|Independent Detector||other controllera|
other flight crewa
|Resolutory Action||flight crew : returned to intended course or assigned course|
|Primary Problem||Flight Crew Human Performance|
|Air Traffic Incident||Pilot Deviation|
During a procedure turn to inbound course at evw, turbulence was encountered and the aircraft descended below the minimum altitude at that segment of the approach for about 30 or 40 seconds. I added power and climbed back to the appropriate altitude and continued the approach to a landing. Wind on the ground was gusting to 335 KTS and crab correction was 25 degrees. The area, geographically is on the backside of a ridge and I suspect there was some wave activity associated with the turbulence. The only reason for this is that, since the computer somewhere may have recorded an altitude bust, there is not much I can see in hindsight that I could have done to change the situation, other than know ahead of time that there would have been significant downdraft. I believe we went down to about 8600' in a 9300' MEA area, but recovered soon and continued the approach at appropriate altitudes. Callback conversation with reporter revealed the following: reporter was on a missed approach and procedure to attempt a second approach. He was operating in and out of clouds and felt on his first approach it would have required to severely maneuver to get lined up. Elected to miss. Did not clean the aircraft up and in general was not following established procedure for a miss. Felt he knew his position and was keeping the aircraft slow and in confign for the second approach. Center controller noted the altitude deviation and that is when he took action to correct the altitude. Aircraft does not have GPWS, but they do use radio altimeter as a back up in operations in the mountainous terrain. Did not notice the altitude readout, however. Was just intercepting the inbound right when the downdraft encountered. WX was near 1000' and 1 mi. Counseled to be more aggressive applying power on a miss and that ASRS is interested in all types of reports, not just immunity related.
Original NASA ASRS Text
Title: ALT EXCURSION FROM PUBLISHED PROC TURN ALT. WX FACTORS.
Narrative: DURING A PROC TURN TO INBND COURSE AT EVW, TURB WAS ENCOUNTERED AND THE ACFT DSNDED BELOW THE MINIMUM ALT AT THAT SEGMENT OF THE APCH FOR ABOUT 30 OR 40 SECS. I ADDED PWR AND CLBED BACK TO THE APPROPRIATE ALT AND CONTINUED THE APCH TO A LNDG. WIND ON THE GND WAS GUSTING TO 335 KTS AND CRAB CORRECTION WAS 25 DEGS. THE AREA, GEOGRAPHICALLY IS ON THE BACKSIDE OF A RIDGE AND I SUSPECT THERE WAS SOME WAVE ACTIVITY ASSOCIATED WITH THE TURB. THE ONLY REASON FOR THIS IS THAT, SINCE THE COMPUTER SOMEWHERE MAY HAVE RECORDED AN ALT BUST, THERE IS NOT MUCH I CAN SEE IN HINDSIGHT THAT I COULD HAVE DONE TO CHANGE THE SITUATION, OTHER THAN KNOW AHEAD OF TIME THAT THERE WOULD HAVE BEEN SIGNIFICANT DOWNDRAFT. I BELIEVE WE WENT DOWN TO ABOUT 8600' IN A 9300' MEA AREA, BUT RECOVERED SOON AND CONTINUED THE APCH AT APPROPRIATE ALTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR WAS ON A MISSED APCH AND PROC TO ATTEMPT A SECOND APCH. HE WAS OPERATING IN AND OUT OF CLOUDS AND FELT ON HIS FIRST APCH IT WOULD HAVE REQUIRED TO SEVERELY MANEUVER TO GET LINED UP. ELECTED TO MISS. DID NOT CLEAN THE ACFT UP AND IN GENERAL WAS NOT FOLLOWING ESTABLISHED PROC FOR A MISS. FELT HE KNEW HIS POS AND WAS KEEPING THE ACFT SLOW AND IN CONFIGN FOR THE SECOND APCH. CENTER CTLR NOTED THE ALT DEVIATION AND THAT IS WHEN HE TOOK ACTION TO CORRECT THE ALT. ACFT DOES NOT HAVE GPWS, BUT THEY DO USE RADIO ALTIMETER AS A BACK UP IN OPS IN THE MOUNTAINOUS TERRAIN. DID NOT NOTICE THE ALT READOUT, HOWEVER. WAS JUST INTERCEPTING THE INBND R WHEN THE DOWNDRAFT ENCOUNTERED. WX WAS NEAR 1000' AND 1 MI. COUNSELED TO BE MORE AGGRESSIVE APPLYING PWR ON A MISS AND THAT ASRS IS INTERESTED IN ALL TYPES OF RPTS, NOT JUST IMMUNITY RELATED.
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.