I used to be a pilot for a regional and only have experience in relatively large twin turboprops. However, while traveling on a B767 out of San Juan PR, the flaps were not extended for takeoff, they never moved (watched them the whole taxi out). From where I was seated, I couldn’t tell if the leading edge devices were deployed or not. Is there any reason that this technique would have been used? It’s definitely out of the norm. Obviously the takeoff was uneventful.
You don’t need flaps for takeoff if the runway is long enough (08/26 at SJU is 10,000 feet, much longer than most), or if your takeoff weight is low enough. As you know, they produce drag as well as lift.
SJU does not have noise abatement procedures, so that isn’t it.
Granted, anything can get airborne if a runway is long enough and if the speed required doesn’t exceed the rating for the tires, but the flights’ passenger load was full and the flight was from SJU to CLT about 2.5 hr duration but not being familiar with the 76 I’m not sure what the fuel weight was. The only aircraft of large size that normally takes off clean winged that I’m familiar with is the F-100. I had never seen it done in anything larger and I was wondering the significance of using this technique since every other time I have been on a 76 it had leading edge devices as well as flaps at the typical setting for takeoff. It was rwy 8 at SJU by the way.
Eureka! Upon reading another post on another site, I learned the norm is flaps 1 which partially extends the leading edge devices and the trailing edge devices remain stowed