Loss of hydraulic pressure in left system results in no nose steering and excursion from runway.

Attributes
ACN	167302
Time
Date	199101
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl
State Reference	GA
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial
Experience	flight time last 90 days : 60 flight time total : 10100 flight time type : 600
ASRS Report	167302
Person 2
Affiliation	company : air carrier
Function	instruction : trainee
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

On approach at bhm, lost left hydraulic fluid on large transport. Directed to atl for maintenance. We did the hydraulic loss of fluid checklist and pulled the circuit breaker to stop the ptu until we started an approach in atl. We reset the circuit breaker on approach and found ptu did not work. We extended flaps and gear by alternate method. On landing we had no nose wheel steering and with full rudder and full left braking we were unable to control drift of aircraft and drifted off right side of runway about 4'. We need to have a way that we can get the left reverser to work with failure of ptu or some way to control the nose wheel steering from another hydraulic system. Callback conversation with reporter revealed the following: ptu is a xfer unit that enables one hydraulic system to use pressure from the other. 1 problem some fluid must be in the failed system. In this case, the left system lost all fluid resulting in no nose steering or hydraulic pressure to activate the left engine reverse system, result right gear off the runway. No damage to the aircraft. Says in the widebody transport sister aircraft, the reserve hydraulic system powers the brakes plus the nose steering. This was not built into the large transport. Seems strange because the 2 aircraft are considered for a common type rating.

Original NASA ASRS Text

Title: LOSS OF HYDRAULIC PRESSURE IN LEFT SYSTEM RESULTS IN NO NOSE STEERING AND EXCURSION FROM RWY.

Narrative: ON APCH AT BHM, LOST LEFT HYD FLUID ON LGT. DIRECTED TO ATL FOR MAINT. WE DID THE HYD LOSS OF FLUID CHKLIST AND PULLED THE CB TO STOP THE PTU UNTIL WE STARTED AN APCH IN ATL. WE RESET THE CB ON APCH AND FOUND PTU DID NOT WORK. WE EXTENDED FLAPS AND GEAR BY ALTERNATE METHOD. ON LNDG WE HAD NO NOSE WHEEL STEERING AND WITH FULL RUDDER AND FULL LEFT BRAKING WE WERE UNABLE TO CTL DRIFT OF ACFT AND DRIFTED OFF RIGHT SIDE OF RWY ABOUT 4'. WE NEED TO HAVE A WAY THAT WE CAN GET THE LEFT REVERSER TO WORK WITH FAILURE OF PTU OR SOME WAY TO CTL THE NOSE WHEEL STEERING FROM ANOTHER HYD SYS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: PTU IS A XFER UNIT THAT ENABLES ONE HYD SYS TO USE PRESSURE FROM THE OTHER. 1 PROB SOME FLUID MUST BE IN THE FAILED SYS. IN THIS CASE, THE LEFT SYS LOST ALL FLUID RESULTING IN NO NOSE STEERING OR HYD PRESSURE TO ACTIVATE THE LEFT ENG REVERSE SYS, RESULT RIGHT GEAR OFF THE RWY. NO DAMAGE TO THE ACFT. SAYS IN THE WDB SISTER ACFT, THE RESERVE HYD SYS POWERS THE BRAKES PLUS THE NOSE STEERING. THIS WAS NOT BUILT INTO THE LGT. SEEMS STRANGE BECAUSE THE 2 ACFT ARE CONSIDERED FOR A COMMON TYPE RATING.

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.