When the flight crew of a g-iv sideslipped the jet to transfer fuel while at FL450 the right side (f...

Attributes
ACN	1093517
Time
Date	201305
Local Time Of Day	0601-1200
Place
Locale Reference	ZTL.ARTCC
State Reference	GA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Gulfstream IV / G350 / G450
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Altimeter
Person 1
Function	Captain
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 15200 Flight Crew Type 400
Events
Anomaly	Aircraft Equipment Problem Less Severe Inflight Event / Encounter Fuel Issue

Narrative:

While in cruise the second officer who was flying from the left seat decided to balance the fuel load. As per manufacturer's limitations; at this altitude; the only way to transfer fuel is to use a slight slip of the aircraft. Altimeters were checked before takeoff with the captain's side (the number 1) reading the same as the co-pilot's side (the number 2). At altitude the number 1 side read FL450 and the number 2 side read FL450; +60 ft. The first officer (pilot flying) applied rudder trim to slip the aircraft. The number 1 altimeter connected to the autopilot; which was flying the aircraft; stayed at FL450 the number 2 altimeter rose to FLl450 +320 ft. The number 2 altimeter at the time was feeding information to the transponder which transmitted a false altitude of FL450 +320 ft as the aircraft was still at FL450.

Original NASA ASRS Text

Title: When the flight crew of a G-IV sideslipped the jet to transfer fuel while at FL450 the right side (First Officer's) altimeter indicated 45;320 FT verses 45;000.

Narrative: While in cruise the Second Officer who was flying from the left seat decided to balance the fuel load. As per manufacturer's limitations; at this altitude; the only way to transfer fuel is to use a slight slip of the aircraft. Altimeters were checked before takeoff with the Captain's side (the Number 1) reading the same as the Co-pilot's side (the Number 2). At altitude the Number 1 side read FL450 and the Number 2 side read FL450; +60 FT. The First Officer (pilot flying) applied rudder trim to slip the aircraft. The Number 1 altimeter connected to the autopilot; which was flying the aircraft; stayed at FL450 the Number 2 altimeter rose to FLl450 +320 FT. The Number 2 altimeter at the time was feeding information to the transponder which transmitted a false altitude of FL450 +320 FT as the aircraft was still at FL450.

Data retrieved from NASA's ASRS site as of July 2013 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.

When the flight crew of a g-iv sideslipped the jet to transfer fuel while at FL450 the right side (first officer's) altimeter indicated 45;320 ft verses 45;000.