Due to decreased aircraft performance, aircraft unable to maintain assigned altitude.

Attributes
ACN	492969
Time
Date	200011
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zme.artcc
State Reference	TN
Altitude	msl bound lower : 36500 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme.artcc
Operator	general aviation : personal
Make Model Name	IAI1124/1124A/Westwind
Operating Under FAR Part	Part 135
Flight Phase	climbout : vacating altitude cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zme.artcc
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : first officer
Qualification	pilot : cfi pilot : instrument pilot : multi engine pilot : atp
Experience	flight time last 90 days : 38 flight time total : 20000 flight time type : 3009
ASRS Report	492969
Person 2
Affiliation	other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : commercial pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 40 flight time total : 10000 flight time type : 800
ASRS Report	491477
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : published procedure non adherence : company policies non adherence : clearance other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance other
Consequence	faa : reviewed incident with flight crew
Miss Distance	vertical : 1500
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were level at FL330. Center gave us FL370 with 4 1/2 mins to climb. The captain accepted the climb and I started the clock. At 36500 ft captain asked center, 'how are we doing on time?' center gave us 15 seconds. We showed 35 seconds. The captain then tried to increase climb. We did make our FL370 altitude ok. Shortly after leveling we noticed that airspeed was dropping/behind power curve. The captain said we have to go down. I asked center for lower. We were advised that we had traffic at FL350. I advised that our aircraft '...would not continue to fly, we had a problem...give us a turn as we can't maintain altitude.' center gave us a turn. We descended to 36500 ft and stayed there. The 500 ft descent regained sufficient airspeed to fix the problem. We knew we only needed 500 ft. We were communicating with center and didn't feel a need to declare an emergency.

Original NASA ASRS Text

Title: DUE TO DECREASED ACFT PERFORMANCE, ACFT UNABLE TO MAINTAIN ASSIGNED ALT.

Narrative: WE WERE LEVEL AT FL330. CTR GAVE US FL370 WITH 4 1/2 MINS TO CLB. THE CAPT ACCEPTED THE CLB AND I STARTED THE CLOCK. AT 36500 FT CAPT ASKED CTR, 'HOW ARE WE DOING ON TIME?' CTR GAVE US 15 SECONDS. WE SHOWED 35 SECONDS. THE CAPT THEN TRIED TO INCREASE CLB. WE DID MAKE OUR FL370 ALT OK. SHORTLY AFTER LEVELING WE NOTICED THAT AIRSPD WAS DROPPING/BEHIND PWR CURVE. THE CAPT SAID WE HAVE TO GO DOWN. I ASKED CTR FOR LOWER. WE WERE ADVISED THAT WE HAD TFC AT FL350. I ADVISED THAT OUR ACFT '...WOULD NOT CONTINUE TO FLY, WE HAD A PROB...GIVE US A TURN AS WE CAN'T MAINTAIN ALT.' CTR GAVE US A TURN. WE DSNDED TO 36500 FT AND STAYED THERE. THE 500 FT DSCNT REGAINED SUFFICIENT AIRSPD TO FIX THE PROB. WE KNEW WE ONLY NEEDED 500 FT. WE WERE COMMUNICATING WITH CTR AND DIDN'T FEEL A NEED TO DECLARE AN EMER.

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.