Captain of an ATR42 feathered both propellers just before completing a stop during parking resulting...

Attributes
ACN	335712
Time
Date	199605
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : okc
State Reference	OK
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	ATR 42
Operating Under FAR Part	Part 121
Flight Phase	ground : parked ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 400 flight time total : 10500 flight time type : 1500
ASRS Report	335712
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	conflict : ground critical other anomaly other anomaly other
Independent Detector	other flight crewa other other : unspecified
Resolutory Action	none taken : detected after the fact none taken : unable
Consequence	other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Was taxiing to parking in okc. I was almost to a stop with #1 engine shut down when I feathered #2 propeller. I had brake pressure at that time to stop head-on. Then marshaller started running backwards and signaling a right turn. I allowed the aircraft to turn and released brake pressure. When signaled to 'panic stop' we had no brakes. Due to close proximity of gpu, 4-5 ft, we hit it. Hitting gpu was unavoidable due to position of equipment. Callback conversation with reporter revealed the following information: the reporter stated that the reason that he did not have any brake pressure with which to stop the aircraft was due to the fact that he had the left engine already shut down and he had just feathered the right propeller. This action caused the complete loss of all hydraulic pressure since both pumps are driven by the propellers turning. There is an emergency electric driven pump to use for the gear and emergency braking only. He said that he knew at once why he had no brake, but it was too late. He further stated that the company has had other similar incidents but that there had been no alert notices issued of the incidents by the company through which other pilots could learn by other pilot experiences. The aircraft was an ATR42.

Original NASA ASRS Text

Title: CAPT OF AN ATR42 FEATHERED BOTH PROPS JUST BEFORE COMPLETING A STOP DURING PARKING RESULTING IN RUNNING INTO A GND PWR UNIT WHEN ALL BRAKE PRESSURE WAS LOST DUE TO THE FEATHERED PROPS. THERE WAS ONLY MINOR DAMAGE TO THE NOSE CONE.

Narrative: WAS TAXIING TO PARKING IN OKC. I WAS ALMOST TO A STOP WITH #1 ENG SHUT DOWN WHEN I FEATHERED #2 PROP. I HAD BRAKE PRESSURE AT THAT TIME TO STOP HEAD-ON. THEN MARSHALLER STARTED RUNNING BACKWARDS AND SIGNALING A R TURN. I ALLOWED THE ACFT TO TURN AND RELEASED BRAKE PRESSURE. WHEN SIGNALED TO 'PANIC STOP' WE HAD NO BRAKES. DUE TO CLOSE PROX OF GPU, 4-5 FT, WE HIT IT. HITTING GPU WAS UNAVOIDABLE DUE TO POS OF EQUIP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT THE REASON THAT HE DID NOT HAVE ANY BRAKE PRESSURE WITH WHICH TO STOP THE ACFT WAS DUE TO THE FACT THAT HE HAD THE L ENG ALREADY SHUT DOWN AND HE HAD JUST FEATHERED THE R PROP. THIS ACTION CAUSED THE COMPLETE LOSS OF ALL HYD PRESSURE SINCE BOTH PUMPS ARE DRIVEN BY THE PROPS TURNING. THERE IS AN EMER ELECTRIC DRIVEN PUMP TO USE FOR THE GEAR AND EMER BRAKING ONLY. HE SAID THAT HE KNEW AT ONCE WHY HE HAD NO BRAKE, BUT IT WAS TOO LATE. HE FURTHER STATED THAT THE COMPANY HAS HAD OTHER SIMILAR INCIDENTS BUT THAT THERE HAD BEEN NO ALERT NOTICES ISSUED OF THE INCIDENTS BY THE COMPANY THROUGH WHICH OTHER PLTS COULD LEARN BY OTHER PLT EXPERIENCES. THE ACFT WAS AN ATR42.

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.

Captain of an ATR42 feathered both propellers just before completing a stop during parking resulting in running into a ground power unit when all brake pressure was lost due to the feathered propellers. There was only minor damage to the nose cone.