A B737NG flight crew noticed left engine bleed pressure was low on taxi out. They tried a takeoff bu...

Attributes
ACN	792798
Time
Date	200806
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Aircraft 1
Controlling Facilities	tower : zzz.tower
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground : takeoff roll
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	792798
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa
Resolutory Action	flight crew : rejected takeoff
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

During taxi out; first officer noted right engine bleed pressure 18 psi and left engine bleed pressure approximately 3-5 psi. Left indication needle not responding to throttle movement. Needles indicated normally on APU air during start sequence. Air panel configured correctly for bleeds on takeoff. We did not make a determination of bleed status at this time per low thrust settings bulletin. On takeoff at stable engine indications; left bleed system indicator remained frozen at 3-5 psi. At toga power setting and takeoff N1. Left indication needle remained frozen at 3-5 psi. No needle movement. Right bleed system indication at 40 psi. I performed a low speed abort at approximately 50-60 KTS and returned to gate. No left side bleed indication on taxi in. With APU air at the gate; left bleed air system needle showed approximately 18 psi. First officer did a great job noting this condition and prevented a probable air return.

Original NASA ASRS Text

Title: A B737NG FLT CREW NOTICED LEFT ENG BLEED PRESSURE WAS LOW ON TAXI OUT. THEY TRIED A TAKEOFF BUT THE PRESSURE REMAINED LOW SO THEY REJECTED THE TAKEOFF AND RETURNED TO THE GATE.

Narrative: DURING TAXI OUT; FO NOTED R ENG BLEED PRESSURE 18 PSI AND L ENG BLEED PRESSURE APPROX 3-5 PSI. L INDICATION NEEDLE NOT RESPONDING TO THROTTLE MOVEMENT. NEEDLES INDICATED NORMALLY ON APU AIR DURING START SEQUENCE. AIR PANEL CONFIGURED CORRECTLY FOR BLEEDS ON TKOF. WE DID NOT MAKE A DETERMINATION OF BLEED STATUS AT THIS TIME PER LOW THRUST SETTINGS BULLETIN. ON TKOF AT STABLE ENG INDICATIONS; L BLEED SYS INDICATOR REMAINED FROZEN AT 3-5 PSI. AT TOGA PWR SETTING AND TKOF N1. L INDICATION NEEDLE REMAINED FROZEN AT 3-5 PSI. NO NEEDLE MOVEMENT. R BLEED SYS INDICATION AT 40 PSI. I PERFORMED A LOW SPD ABORT AT APPROX 50-60 KTS AND RETURNED TO GATE. NO L SIDE BLEED INDICATION ON TAXI IN. WITH APU AIR AT THE GATE; L BLEED AIR SYS NEEDLE SHOWED APPROX 18 PSI. FO DID A GREAT JOB NOTING THIS CONDITION AND PREVENTED A PROBABLE AIR RETURN.

Data retrieved from NASA's ASRS site as of May 2009 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.

A B737NG flight crew noticed left engine bleed pressure was low on taxi out. They tried a takeoff but the pressure remained low so they rejected the takeoff and returned to the gate.