Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 47150307208016 (LWP 21288)]
0x0000000000497c4a in ~FGTower (this=0x8e3f9f8) at tower.cxx:227
227                     delete ground;
(gdb) bt
#0  0x0000000000497c4a in ~FGTower (this=0x8e3f9f8) at tower.cxx:227
#1  0x0000000000476a0e in ~FGATCMgr (this=0x8e3f870) at ATCmgr.cxx:84
#2  0x0000000000449f55 in ~FGGlobals (this=0xc487b0) at globals.cxx:137
#3  0x000000000041da70 in fgExitCleanup () at bootstrap.cxx:251
#4  0x00002ae20848a419 in exit () from /lib/libc.so.6
#5  0x000000000045e7dd in fgExit (status=0) at util.cxx:115
#6  0x0000000000432cc6 in do_exit (arg=0x13f915c0) at fg_commands.cxx:226
#7  0x0000000000982fb6 in SGBinding::fire (this=0xe9bad0) at SGBinding.cxx:60
#8  0x00000000006bf357 in action_callback (object=<value optimized out>)
    at dialog.cxx:265
#9  0x00000000009985d7 in puOneShot::doHit ()
#10 0x000000000099732a in puObject::checkHit ()
#11 0x0000000000997429 in puObject::checkKey ()
#12 0x0000000000994e25 in puGroup::checkKey ()
#13 0x0000000000994e25 in puGroup::checkKey ()
#14 0x0000000000991fa2 in puKeyboard ()
#15 0x00000000006e1568 in keyHandler (key=13, keymod=0, mousex=640, mousey=512)
    at input.cxx:1105
#16 0x000000000046749a in fgOSMainLoop () at fg_os_sdl.cxx:195
#17 0x000000000041eba9 in fgMainInit (argc=1, argv=0x7fffa4f4df08) at main.cxx:1075
#18 0x000000000041db1d in main (argc=1, argv=0x7fffa4f4df08) at bootstrap.cxx:220