On Sunday afternoon a JetBlue Airbus A320 (N646JB) departed JFK for Long Beach. The aircraft later returned to JFK after the airline announced that the aircraft had hit birds on climb out. That was later updated to hail, and later again diagnosing the cause of the early return as a tail strike on departure from runway 22R.
Sometime between the announcement of birds and the tail strike, the hail was the official story and it reminded me something Boeing Commercial Airplanes CEO, Jim Albaugh, said during the media roundtable two weeks ago week. He mentioned that composites scaled up much better than they scaled down. I asked why that was and if it was related to the pace of manufacturing. I was surprised to find out it had more to do with hail and other impacts. Here's his reply:
In a high cycle environment where the aircraft is on the ground more frequently during the day being serviced, loaded and unloaded for flight, the chances of ground service equipment hitting the airframe goes up. It sheds some interesting light about the challenges for designing the future narrowbody replacements.It's really not the ability to build. Composites are very strong, and we have sized the composite wing of the 787 to have the strength necessary to lift the airplane, but also resist impact - hail, mechanical impacts - start scaling it down and you have to have the same thickness for a smaller airplane that you have on a bigger airplane, not because of the stresses caused by lift, its really the impact of hail, equipment impacting the wings, you really don't get the efficiency scaling down right now, you get the efficiency scaling up.
It leads me to a broader follow up for discussion here. How does alumimum scale in comparison to composite? At what size airplane does aluminum become less efficient? How does hail and ground equipment impact play into this?