Two pilots report they were notified by ground crew personnel that heavy black smoke was coming out ...

Attributes
ACN	1255726
Time
Date	201504
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Parked
Component
Aircraft Component	Hydraulic System Pump
Person 1
Function	First Officer
Experience	Flight Crew Last 90 Days 145 Flight Crew Type 500
Person 2
Function	Captain
Experience	Flight Crew Last 90 Days 150 Flight Crew Type 12000
Events
Anomaly	Aircraft Equipment Problem Less Severe Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

Narrative:

While in the cockpit and waiting for an amended flight release; due to added MEL requiring unpressurized flight; ground crew notified the cockpit that smoke was coming from the wheel well and intensifying. I called ground control to tell them that heavy smoke was coming from the wheel well and to notify and send the fire department to gate. I depowered the aircraft; confirmed that no one was aboard; and exited through the forward entry door.[recommend] turn off electric hydraulic pumps if longer than normal time is taken to generate paperwork. The reason for the delay in getting the new release was that ATC would not approve low altitude routing required when having to fly unpressurized. Smoke in wheel well caused by overheating electric hydraulic pump.

Original NASA ASRS Text

Title: Two pilots report they were notified by ground crew personnel that heavy black smoke was coming out from the Main wheel well of their B737NG aircraft. Maintenance Technicians recognized the smell of the smoke as hydraulic related and instructed pilots to shut off the electric hydraulic pumps.

Narrative: While in the cockpit and waiting for an amended flight Release; due to added MEL requiring unpressurized flight; ground crew notified the cockpit that smoke was coming from the wheel well and intensifying. I called Ground Control to tell them that heavy smoke was coming from the wheel well and to notify and send the Fire Department to Gate. I depowered the aircraft; confirmed that no one was aboard; and exited through the forward entry door.[Recommend] Turn off electric hydraulic pumps if longer than normal time is taken to generate paperwork. The reason for the delay in getting the new Release was that ATC would not approve low altitude routing required when having to fly unpressurized. Smoke in wheel well caused by overheating electric hydraulic pump.

Data retrieved from NASA's ASRS site 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.

Two pilots report they were notified by ground crew personnel that heavy black smoke was coming out from the main wheel well of their B737NG aircraft. Maintenance technicians recognized the smell of the smoke as hydraulic related and instructed pilots to shut off the electric hydraulic pumps.