Date: 201308
Local time of day: 1201-1800
Location: IND.Tower, IN
Flight conditions: VMC
Aircraft: DC-10 30
Flight phase: Climb
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: Captain; Pilot Flying
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Chart Or Publication; Human Factors; Procedure
Primary problem: Ambiguous

Narrative: Pilot Flying (PF) briefed ROCKY7 SID off 23L. Taking runway; we were cleared for takeoff and to fly heading 242. Per the SID; I expected the PF to fly Heading 227(runway heading) to IFVJ 2.3 DME and turn right to 242 as assigned for a westerly departure. FMS was setup to display DME and I was prepared to call the turn. However; I was surprised when at 500 FT; the PF called for PROF and Heading Select and was already turning from runway heading to 242. It was too late and unsafe that low to the ground in a critical phase of flight to discuss/correct/argue over such a small turn approximately 1.3 miles early. I quickly glanced to my right; scanned TCAS; and realized there were no departures off 23R. Remainder of flight was normal. Later on; I brought up the apparent deviation from the SID. After much discussion; PF believed a Tower heading assignment negates the SID instructions. I would normally agree; but not since our PDC clearance was for the ROCKY7 and clearly states 'as assigned Heading' and 242 being one of the three headings listed.  I had just watched another aircraft depart before us while we sat on the runway in 'position and hold' status waiting for aircraft separation and ATC clearance to depart. That aircraft did not turn at 500 FT and (to my eyes) was already at 1;000 FT and cleaning up before turning right to 242 heading well southwest of the airport boundary. Upon landing; PF called INDY Tower and did not receive a satisfactory answer either. According to whomever he spoke with; no action had been taken. Nothing had been noticed out of the ordinary. Tower issued instructions were vague. At other airports; Tower would most likely clear an aircraft using verbiage; 'Cleared; Rocky7 Departure; fly heading 242; cleared for Takeoff'. Or similar. Different understandings of Tower clearance between the pilots.  Maybe I'm wrong; and we did as Tower cleared us. Clearer communication from Tower or a query from us about ATC's true intent. A better solution would be to use an FMS flyover waypoint on the departure versus an ILS DME fix. INDY is one of a few large airports that still utilize this old method of separation/track for modern aircraft. It requires crews add an extra step in the cockpit setup process; a call out by the PM while in a critical phase of flight; and opens the door for errors. Technology has alleviated this step at most other airports.


Second narrative: Briefed Rocky 7; Tower clearance 'Cleared for takeoff; on departure fly heading 242' Turned to heading 242 at 500 FT on departure. No comment by Departure Control. During debrief First Officer thought we needed to go straight to IFVJ/2.3 prior to turning. I felt 'on departure fly heading 242' was a vector of SID. Called Indy Tower to verify. They said we should have turned at IFVJ/2.3. But had no objection with our early turn? [At other airports] 'On departure fly heading 160' is a vector off the SID. Why does the same instruction mean something different in KIND? If the want you to go to IFVJ/2.7 They should say. 'cleared for takeoff; on SID fly 242 heading' or 'fly Rocky 7 heading 242' Something clearly highlighting this is not a vector off the SID.


Synopsis: Air Carrier flight crew reports a different interpretation of Tower instructions to fly heading 242 after takeoff with a PDC of the ROCKY7 departure.