Date: 201604
Local time of day: 0001-0600
Location: MEM.Airport, TN
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight phase: Other Towing
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Communication Breakdown; Confusion; Fatigue
Second reporter function: Captain; Pilot Flying
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Became Reoriented
Contributing factors: Human Factors; Company Policy
Primary problem: Human Factors

Narrative: Assigned parking gate ZZZ via spot ZZ. ACARS message noted tow in. Contacted ramp control approaching Taxiway ZZ and cleared in. Instructed to hold short of drive lane. Aircraft stopped prior to taxi line for gate ZZZ facing west; brake set; taxi light off. After some time; tug refused to approach the aircraft and began to flash lights to indicate they wanted additional action from the crew prior to hook up. After consultation between crew members we elected to position the aircraft to facilitate a tow that the tug crew was willing to accommodate. After further review; it appears we should have held position until the tug crew approached the aircraft in its previous orientation.Causes were a combination of ambiguous instructions from ramp tower and a failure of the flight crew to clarify. Flight crew should have done a more detailed review of parking notes to ensure that all procedures were adhered to. Compounding the error was a tug crew that insisted on using non standard communication (flashing lights to message the crew). Suggest crews review and follow Jepps parking notes irrespective of outside influences.


Second narrative: 'In Range'- flight assigned gate ZZZ; tow-in; blast critical gate; ground power available.'Spot XX' - ramp tower verbally confirms gate ZZZ with additional statement 'hold short of the 'drive lane' for tow-in the tug will meet you there'.Captain stopped aircraft prior to the taxi lane (intersection) leading straight into the hangar; set the parking brake; turned off the taxi light. The tug was sitting facing south toward the heavy weight facility centered on the taxi line leading to the hangar and proceeded to flash its lights at the aircraft without moving forward to retrieve the aircraft. After 30-45 seconds with no movement from the tug; the Captain after a short discussion with the First Officer wrongly taxied the aircraft to face the tug; shut down the engines and was then towed to the gate. While under tow; the crew reviewed notes for specific gates to find that gate ZZZ requires a tow-in from a west facing position at the taxi entrance to the hangar.Cause:Captain did not follow through on plan to park the aircraft short of the taxi lane to the hangar and shutdown for tow-in. Flight crew failed to read all notes due to perceived familiarity with ZZZ ramp. Ramp tower issued what the flight crew perceived to be clear yet misleading/non-standard tow-in directions. Tug crew demonstrated non-standard behavior by not moving in a timely manner toward the aircraft once it parked and shut off taxi light and by flashing its lights at the aircraft - all of which was perceived by the crew as 'pull up to the tug' for towing (in light of the ramp tower directions).A level of crew fatigue - perceived by the Captain as normal. Two nights prior a major weather event caused a significant delay of departure from ZZZ. Crew also experienced an additional delay. Crew did not arrive at the hotel until after XA:30 local (w/FAR extension). Captain raised the concern and crew discussed sleep periods during preflight brief next evening and determined each crew member experienced approximately 4 hours of sleep during the rest period - no action taken. One night prior to event crew again experienced another delayed departure from ZZZ and another outbound maintenance event that required a return to the gate adding approximately a 1 1/2 hour delay. Crew discussed sleep period again during the next evening preflight brief and concluded 5-6 hours of sleep was about it. So; with 20/20 hindsight; in reality the crew had approximately 10 hours of sleep in the two rest periods. Crew did use hub sleep facility as a matter of habit; so an undetermined amount of sleep was added during hub turn.Suggestions:Captain correctly had the parking brake set - once a question arose as to our correct positioning for tow-in; event could have been prevented by contacting ramp tower for clarification. Flight crew should have read all notes pertaining to parking spot regardless of perceived familiarity - adherence to required duties would have prevented the event. Ramp tower should use standard phraseology as printed on the parking diagram - 'stop at intersection of lead-in line to hangar heading WEST' IF they are going to issue those directives AT ALL - procedural change to prevent future event.Tug crew should not use NON-STANDARD procedures such as flashing their lights to attempt to communicate with the aircraft. There was also failure of the tug to move toward the aircraft in a timely manner once it was parked in the correct position for tow-in. Captain discussed the event once parked at the gate with tug crew and was told that they flash the lights to 'tell the crew to shutdown the engines'.Captain was actively assessing crew fatigue; but took no action due to 'normalization of deviance' - we accepted our rest periods as 'normal' - Captain could have possibly prevented event by being more aggressive with fatigue call.


Synopsis: An air carrier flight crew reported confusion during transition from taxi-in to tug hook up for the final pull-in to the gate. The tug crew's actions; incomplete instructions from Ramp Tower as to parking instructions; and fatigue contributed to the crew's confusion. In addition; the crew did not follow published procedures for parking at the assigned gate.