Altitude deviation unable to hold altitude due to temperature inversion.

Attributes
ACN	296278
Time
Date	199502
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sdf
State Reference	KY
Altitude	msl bound lower : 42500 msl bound upper : 43000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 96 flight time total : 6911 flight time type : 1655
ASRS Report	296278
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter other non adherence : clearance non adherence : required legal separation
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation other

Narrative:

The aircraft was on a flight from cha to mke and had been cleared by ARTCC to climb and maintain FL430. The flight was a second flight of the day (the first being from cha to sgf to cha), and we had observed that the outside air temperature was some 10-12 degrees warmer than usual on the first flight at FL430. Although we encountered the warmer than usual air temperature during the first flight at FL430 (which is usual for air behind a strong cold frontal boundary), we had no problems in a cruise climb to and then maintaining the flight level (FL430). Our number of passenger was 2 on the first flight and 3 on the second flight. It was during the second trip that we encountered the severe area of temperature inversion (some 30 plus degrees warmer than isa). We had just leveled the aircraft when we experienced the extremely warm air, and we immediately contacted the ARTCC controller and requested FL390 as the aircraft would not accelerate to its standard mach speed: rather the aircraft was losing speed in the thin air and began to settle slowly as we were conversing with the controller. There was opposing traffic at FL410 within 5 mi of our position and the ARTCC controller advised that he could not give us a descent clearance until we had cleared the traffic. When the opposing traffic passed us, we had settled approximately 250 ft below FL430 as we could not do anything more than hold attitude while in the inversion. Even with full climb power available to us at FL430, we were continuing to settle very slowly as we awaited clearance to FL390: and when the controller advised that we could descend to and maintain FL390, the aircraft had settled approximately 450 ft below FL430. We then descended to FL390 and completed the flight to mke with no further problems. Our airspeed came up to normal cruise (.79 mach) and we noticed that the outside air temperature had decreased some 10 degrees. During our return trip to cha at FL410, we again encountered warm air, but nothing similar to the type of inversion that we encountered as described herein above.

Original NASA ASRS Text

Title: ALTDEV UNABLE TO HOLD ALT DUE TO TEMP INVERSION.

Narrative: THE ACFT WAS ON A FLT FROM CHA TO MKE AND HAD BEEN CLRED BY ARTCC TO CLB AND MAINTAIN FL430. THE FLT WAS A SECOND FLT OF THE DAY (THE FIRST BEING FROM CHA TO SGF TO CHA), AND WE HAD OBSERVED THAT THE OUTSIDE AIR TEMP WAS SOME 10-12 DEGS WARMER THAN USUAL ON THE FIRST FLT AT FL430. ALTHOUGH WE ENCOUNTERED THE WARMER THAN USUAL AIR TEMP DURING THE FIRST FLT AT FL430 (WHICH IS USUAL FOR AIR BEHIND A STRONG COLD FRONTAL BOUNDARY), WE HAD NO PROBS IN A CRUISE CLB TO AND THEN MAINTAINING THE FLT LEVEL (FL430). OUR NUMBER OF PAX WAS 2 ON THE FIRST FLT AND 3 ON THE SECOND FLT. IT WAS DURING THE SECOND TRIP THAT WE ENCOUNTERED THE SEVERE AREA OF TEMP INVERSION (SOME 30 PLUS DEGS WARMER THAN ISA). WE HAD JUST LEVELED THE ACFT WHEN WE EXPERIENCED THE EXTREMELY WARM AIR, AND WE IMMEDIATELY CONTACTED THE ARTCC CTLR AND REQUESTED FL390 AS THE ACFT WOULD NOT ACCELERATE TO ITS STANDARD MACH SPD: RATHER THE ACFT WAS LOSING SPD IN THE THIN AIR AND BEGAN TO SETTLE SLOWLY AS WE WERE CONVERSING WITH THE CTLR. THERE WAS OPPOSING TFC AT FL410 WITHIN 5 MI OF OUR POS AND THE ARTCC CTLR ADVISED THAT HE COULD NOT GIVE US A DSCNT CLRNC UNTIL WE HAD CLRED THE TFC. WHEN THE OPPOSING TFC PASSED US, WE HAD SETTLED APPROX 250 FT BELOW FL430 AS WE COULD NOT DO ANYTHING MORE THAN HOLD ATTITUDE WHILE IN THE INVERSION. EVEN WITH FULL CLB PWR AVAILABLE TO US AT FL430, WE WERE CONTINUING TO SETTLE VERY SLOWLY AS WE AWAITED CLRNC TO FL390: AND WHEN THE CTLR ADVISED THAT WE COULD DSND TO AND MAINTAIN FL390, THE ACFT HAD SETTLED APPROX 450 FT BELOW FL430. WE THEN DSNDED TO FL390 AND COMPLETED THE FLT TO MKE WITH NO FURTHER PROBS. OUR AIRSPD CAME UP TO NORMAL CRUISE (.79 MACH) AND WE NOTICED THAT THE OUTSIDE AIR TEMP HAD DECREASED SOME 10 DEGS. DURING OUR RETURN TRIP TO CHA AT FL410, WE AGAIN ENCOUNTERED WARM AIR, BUT NOTHING SIMILAR TO THE TYPE OF INVERSION THAT WE ENCOUNTERED AS DESCRIBED HEREIN ABOVE.

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.