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|
Attributes | |
ACN | 570008 |
Time | |
Date | 200301 |
Day | Sat |
Local Time Of Day | 0601 To 1200 |
Place | |
Locale Reference | navaid : sju.vortac |
State Reference | PR |
Altitude | msl bound lower : 4650 msl bound upper : 4800 |
Environment | |
Flight Conditions | VMC |
Light | Daylight |
Aircraft 1 | |
Controlling Facilities | artcc : zsu.artcc |
Operator | general aviation : corporate |
Make Model Name | Learjet 45 |
Operating Under FAR Part | Part 91 |
Navigation In Use | other |
Flight Phase | cruise : level |
Flight Plan | IFR |
Person 1 | |
Affiliation | company : corporate |
Function | flight crew : captain oversight : pic |
Qualification | pilot : atp |
Experience | flight time last 90 days : 25 flight time total : 10100 flight time type : 700 |
ASRS Report | 570008 |
Person 2 | |
Affiliation | company : corporate |
Function | flight crew : first officer |
Events | |
Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather inflight encounter other non adherence : clearance other anomaly |
Independent Detector | other flight crewa other flight crewb |
Resolutory Action | controller : issued new clearance flight crew : regained aircraft control flight crew : exited adverse environment flight crew : took evasive action |
Supplementary | |
Problem Areas | ATC Human Performance Environmental Factor Weather |
Primary Problem | Weather |
Air Traffic Incident | Pilot Deviation |
Narrative:
I had climbed to FL470 for wind. The sat was isa -- 10 degrees, mach .70, weight was 19000 pounds per the manual. I requested a FL470-FL490 block to climb and descend back to FL470 to accelerate to cruise. At FL480, a sudden rise in temperature to isa +5 degrees happened, probably due to a front east of florida, causing a warm air influx at altitude. There was nothing in the temperature charts about this. The mach decreased to .68 mach, and the aircraft wouldn't hold altitude. I descended to FL470, and the aircraft would not hold speed. I had no choice except to ask for a descent to FL450. The controller would not give a lower altitude and told me miami would give it to us. I had to descend to keep the speed from decreasing further. The controller finally gave me FL450 after I was at FL465. No problems after that, as the temperature was 15 at -5 at FL450. I have not seen this temperature flux before. But I will pay more attention to fronts and watch the sat more closely.
Original NASA ASRS Text
Title: A LEAR 45 FLC EXPERIENCES HIGH ALT WINDSHEAR AND IS UNABLE TO MAINTAIN AIRSPD AND ALT.
Narrative: I HAD CLBED TO FL470 FOR WIND. THE SAT WAS ISA -- 10 DEGS, MACH .70, WT WAS 19000 LBS PER THE MANUAL. I REQUESTED A FL470-FL490 BLOCK TO CLB AND DSND BACK TO FL470 TO ACCELERATE TO CRUISE. AT FL480, A SUDDEN RISE IN TEMP TO ISA +5 DEGS HAPPENED, PROBABLY DUE TO A FRONT E OF FLORIDA, CAUSING A WARM AIR INFLUX AT ALT. THERE WAS NOTHING IN THE TEMP CHARTS ABOUT THIS. THE MACH DECREASED TO .68 MACH, AND THE ACFT WOULDN'T HOLD ALT. I DSNDED TO FL470, AND THE ACFT WOULD NOT HOLD SPD. I HAD NO CHOICE EXCEPT TO ASK FOR A DSCNT TO FL450. THE CTLR WOULD NOT GIVE A LOWER ALT AND TOLD ME MIAMI WOULD GIVE IT TO US. I HAD TO DSND TO KEEP THE SPD FROM DECREASING FURTHER. THE CTLR FINALLY GAVE ME FL450 AFTER I WAS AT FL465. NO PROBS AFTER THAT, AS THE TEMP WAS 15 AT -5 AT FL450. I HAVE NOT SEEN THIS TEMP FLUX BEFORE. BUT I WILL PAY MORE ATTN TO FRONTS AND WATCH THE SAT MORE CLOSELY.
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.