Narrative:

Crj-200 departed runway 9 at bos; assigned the HYLND1 SID. The aircraft was supposed to fly direct to claww way point; essentially straight ahead. Instead; after becoming airborne; the aircraft immediately turned left to what looked like a north or northwest bound heading. I immediately noticed this; and called bos local east sector; and they turned the aircraft back to the east. The aircraft ended up approximately 4 or 5 miles north of the SID track. Furthermore; there was an aircraft in the departure camera that would be departing runway 4R at the time. If that aircraft had departed a minute or two earlier; a collision could have occurred. I'm not sure what to recommend to prevent this situation; short of not using RNAV SID's. In my opinion; the use of RNAV for SID's is risky. The aircraft are essentially flying themselves on autopilot; and if one small erroneous thing is entered into the aircraft computer; it will turn in any seemingly random direction. At that point; the pilots are essentially along for the ride; unless and until they figure out that something is wrong. I know that RNAV is very popular and a big part of nextgen; but in a busy terminal area; with many aircraft in all directions; at all altitudes; this can be very dangerous. I would recommend that RNAV be used once the aircraft are a bit farther away from the airport; where a mistake would be less likely to be catastrophic. Just because we can use RNAV for SID's doesn't necessarily mean that we should. The use of RNAV SID's certainly does nothing to increase safety; but I can think of many situations where it is outright detrimental.

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Original NASA ASRS Text

Title: A90 Controller described a potential conflict event when a Runway 9 departure assigned the HYLND1 SID made an unexpected left turn corrected prior to any conflict; the Controller indicated RNAV SID's are potentially dangerous.

Narrative: CRJ-200 departed Runway 9 at BOS; assigned the HYLND1 SID. The aircraft was supposed to fly direct to CLAWW way point; essentially straight ahead. Instead; after becoming airborne; the aircraft immediately turned left to what looked like a north or northwest bound heading. I immediately noticed this; and called BOS Local East Sector; and they turned the aircraft back to the east. The aircraft ended up approximately 4 or 5 miles north of the SID track. Furthermore; there was an aircraft in the departure camera that would be departing Runway 4R at the time. If that aircraft had departed a minute or two earlier; a collision could have occurred. I'm not sure what to recommend to prevent this situation; short of not using RNAV SID's. In my opinion; the use of RNAV for SID's is risky. The aircraft are essentially flying themselves on autopilot; and if one small erroneous thing is entered into the aircraft computer; it will turn in any seemingly random direction. At that point; the pilots are essentially along for the ride; unless and until they figure out that something is wrong. I know that RNAV is very popular and a big part of NextGen; but in a busy terminal area; with many aircraft in all directions; at all altitudes; this can be very dangerous. I would recommend that RNAV be used once the aircraft are a bit farther away from the airport; where a mistake would be less likely to be catastrophic. Just because we can use RNAV for SID's doesn't necessarily mean that we should. The use of RNAV SID's certainly does nothing to increase safety; but I can think of many situations where it is outright detrimental.

Data retrieved from NASA's ASRS site as of April 2012 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.