john: good evening, i'm john yang.'s been another fatal plane crash, this one in philadelphia, even as investigators piece together evidence from wednesday's deadly mid-air collision in washington, d.c. last night, a small jet transporting a pediatric patient home to mexico crashed in northeast philadelphia shortly after takeoff read at least seven people died including the six mexican citizens on board. on the ground homes were set , ablaze and at least 19 people were injured. it came as investigators continue their search for answers in the collision of a passenger jet and an army helicopter near washington's airport. that accident claimed 67 lives, the worst u.s. air crash in at least 15 years. randy babbitt is a former administrator of the federal aviation administration and he is also a commercial airline pilot. the faa took its first action yesterday to close off the area around washington reagan national to low altitude, most low altitude helicopter traffic. randy: i think that is a good move, and important it -

i'm john yang.dent trump said today that americans may feel some pain as a result of the north american trade war that's emerging after he imposed sweeping tariffs on mexico and canada. but, mr. trump added, it would be worth the price. retaliatory tariffs were quickly announced by mexico, canada and china, which the president also targeted with import duties. last night, canadian prime minister justin trudeau had a stern warning for americans. >> this is a choice that, yes, will harm canadians, but beyond that, it will have real consequences for you, the american people. john: today, senate minority leader chuck schumer urged mr. trump to reverse course before the tariffs take effect at 12:01 tuesday morning. >> you campaigned on lowering prices. you campaigned on this wallet. but your tariffs will have more money come out of this wallet for so many goods and services. john: the public reaction in canada has been especially strong. kirsten hillman is the canadian ambassador to the united states. ma

for the pbs newshour i'm john yang.eff: and there are many more questions about the safety of the u.s. aviation system and whether other changes might be needed. for a pilot's perspective we're joined by les abend. he's a contributing editor to flying magazine. thank you for being was. >> glad to be here. geoff: the altitude is coming under scrutiny. the "new york times" is reporting today that the helicopter that collided with the passenger jet appears to have been flying too high and outside of its approved flight path at the time of the crash. add to that president trump posted on social media the helicopter was flying too high by a lot. as we await the findings of this investigation based on your experience and your review of the new videos of the crash, what's your best assessment of what transpired? >> well, listen, everything is pure speculation at this point. none of us should be making conjectures or anything of that nature with referenced to what happened. the altitude that is this helicopter might have been f