Air carrier flight crew in B727 attempted to climb above adverse WX but were unable to maintain thei...

Attributes
ACN	430170
Time
Date	199903
Day	Fri
Local Time Of Day	1801 To 2400
Place
State Reference	TN
Altitude	msl bound lower : 38300 msl bound upper : 29000
Environment
Flight Conditions	IMC
Weather Elements	Thunderstorm Ice Turbulence
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zme.artcc
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : instrument pilot : multi engine pilot : atp
Experience	flight time last 90 days : 150 flight time total : 8000 flight time type : 1000
ASRS Report	430170
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather non adherence : clearance non adherence : far
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : regained aircraft control
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were on a flight from mem departing to the west. There was a line of thunderstorms about 20 mi wide, 70 mi to the northwest of mem. In our climb out to our assigned altitude of FL350, we noticed some very intense echoes being displayed on our radar screen at about 20-30 mi ahead of our position. In the moonlight we could see that these thunderstorm cloud tops were built up to a higher altitude than ours. Based on our WX radar presentation we decided to ask ATC for a deviation to the right (north) of our course. Center approved the deviation. We felt this would be the best way to go since the area to the left (south) of our course seemed more concentrated with thunderstorms. However, as we turned, we noticed we would have to fly between 2 thunderstorm cells whose echoes appeared to be about 20 mi apart. As we continued, the cloud tops continued to rise and we asked ATC if we could climb to a higher altitude of FL390. Center approved the altitude change and issued us a clearance to climb and maintain FL390. During the climb we noticed the outside air temperature gauge had decreased to a point in which we needed to turn on engine anti-ice. To prevent ice build-up on the engines (at this temperature in the clouds) we had to activate the engine anti-ice system prior to entering the clouds. Also during the climb, we experienced light to moderate turbulence. In trying to climb over these storms, we initially used a higher rate of climb, however, our airspeed began decreasing. So between FL380 to FL390 in order to maintain our airspeed above the minimum buffet speed, our rate of climb stopped. We had to level off and start a slight descent to allow the airspeed to gradually build back up so we could continue our climb to FL390. (After descending to FL383 it took a couple of mins for the airspeed to build up so we could continue the slow climb to FL390.) after reaching FL390, we were on top of all the WX and continued with the EST of the flight which was uneventful. What I believe caused this problem was not using our onboard WX radar more thoroughly to allow us to circumnav around these storms at a much further distance. (We could have changed range and tilt settings more frequently.) also realizing that once engine anti-ice is turned on, there is less available thrust being produced by the engines (engine bleed air is used to operate the system). With less thrust available, a lower rate of climb is necessary in order to maintain a certain minimum airspeed. And asking ATC for a 'block altitude' if you're unable to reach your assigned altitude. To prevent a recurrence, I believe crews should fully use their onboard WX radar system to determine the best course of action to circumnav thunderstorms. Also, when using engine anti-ice, maintain a lower rate of climb to ensure the airspeed will not bleed off to the point of having to level off before you reach your assigned altitude, and to ask ATC for a block altitude clearance if you see that you are not going to reach your assigned altitude.

Original NASA ASRS Text

Title: ACR FLC IN B727 ATTEMPTED TO CLB ABOVE ADVERSE WX BUT WERE UNABLE TO MAINTAIN THEIR CLB TO THE ASSIGNED ALT BECAUSE OF THEIR WT AND USE OF ENG ANTI-ICE.

Narrative: WE WERE ON A FLT FROM MEM DEPARTING TO THE W. THERE WAS A LINE OF TSTMS ABOUT 20 MI WIDE, 70 MI TO THE NW OF MEM. IN OUR CLBOUT TO OUR ASSIGNED ALT OF FL350, WE NOTICED SOME VERY INTENSE ECHOES BEING DISPLAYED ON OUR RADAR SCREEN AT ABOUT 20-30 MI AHEAD OF OUR POS. IN THE MOONLIGHT WE COULD SEE THAT THESE TSTM CLOUD TOPS WERE BUILT UP TO A HIGHER ALT THAN OURS. BASED ON OUR WX RADAR PRESENTATION WE DECIDED TO ASK ATC FOR A DEV TO THE R (N) OF OUR COURSE. CTR APPROVED THE DEV. WE FELT THIS WOULD BE THE BEST WAY TO GO SINCE THE AREA TO THE L (S) OF OUR COURSE SEEMED MORE CONCENTRATED WITH TSTMS. HOWEVER, AS WE TURNED, WE NOTICED WE WOULD HAVE TO FLY BTWN 2 TSTM CELLS WHOSE ECHOES APPEARED TO BE ABOUT 20 MI APART. AS WE CONTINUED, THE CLOUD TOPS CONTINUED TO RISE AND WE ASKED ATC IF WE COULD CLB TO A HIGHER ALT OF FL390. CTR APPROVED THE ALT CHANGE AND ISSUED US A CLRNC TO CLB AND MAINTAIN FL390. DURING THE CLB WE NOTICED THE OUTSIDE AIR TEMP GAUGE HAD DECREASED TO A POINT IN WHICH WE NEEDED TO TURN ON ENG ANTI-ICE. TO PREVENT ICE BUILD-UP ON THE ENGS (AT THIS TEMP IN THE CLOUDS) WE HAD TO ACTIVATE THE ENG ANTI-ICE SYS PRIOR TO ENTERING THE CLOUDS. ALSO DURING THE CLB, WE EXPERIENCED LIGHT TO MODERATE TURB. IN TRYING TO CLB OVER THESE STORMS, WE INITIALLY USED A HIGHER RATE OF CLB, HOWEVER, OUR AIRSPD BEGAN DECREASING. SO BTWN FL380 TO FL390 IN ORDER TO MAINTAIN OUR AIRSPD ABOVE THE MINIMUM BUFFET SPD, OUR RATE OF CLB STOPPED. WE HAD TO LEVEL OFF AND START A SLIGHT DSCNT TO ALLOW THE AIRSPD TO GRADUALLY BUILD BACK UP SO WE COULD CONTINUE OUR CLB TO FL390. (AFTER DSNDING TO FL383 IT TOOK A COUPLE OF MINS FOR THE AIRSPD TO BUILD UP SO WE COULD CONTINUE THE SLOW CLB TO FL390.) AFTER REACHING FL390, WE WERE ON TOP OF ALL THE WX AND CONTINUED WITH THE EST OF THE FLT WHICH WAS UNEVENTFUL. WHAT I BELIEVE CAUSED THIS PROB WAS NOT USING OUR ONBOARD WX RADAR MORE THOROUGHLY TO ALLOW US TO CIRCUMNAV AROUND THESE STORMS AT A MUCH FURTHER DISTANCE. (WE COULD HAVE CHANGED RANGE AND TILT SETTINGS MORE FREQUENTLY.) ALSO REALIZING THAT ONCE ENG ANTI-ICE IS TURNED ON, THERE IS LESS AVAILABLE THRUST BEING PRODUCED BY THE ENGS (ENG BLEED AIR IS USED TO OPERATE THE SYS). WITH LESS THRUST AVAILABLE, A LOWER RATE OF CLB IS NECESSARY IN ORDER TO MAINTAIN A CERTAIN MINIMUM AIRSPD. AND ASKING ATC FOR A 'BLOCK ALT' IF YOU'RE UNABLE TO REACH YOUR ASSIGNED ALT. TO PREVENT A RECURRENCE, I BELIEVE CREWS SHOULD FULLY USE THEIR ONBOARD WX RADAR SYS TO DETERMINE THE BEST COURSE OF ACTION TO CIRCUMNAV TSTMS. ALSO, WHEN USING ENG ANTI-ICE, MAINTAIN A LOWER RATE OF CLB TO ENSURE THE AIRSPD WILL NOT BLEED OFF TO THE POINT OF HAVING TO LEVEL OFF BEFORE YOU REACH YOUR ASSIGNED ALT, AND TO ASK ATC FOR A BLOCK ALT CLRNC IF YOU SEE THAT YOU ARE NOT GOING TO REACH YOUR ASSIGNED ALT.

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.

Air carrier flight crew in B727 attempted to climb above adverse WX but were unable to maintain their climb to the assigned altitude because of their weight and use of engine anti-ice.