B737 CREW DEPARTING OUT OF HOU BELIEVES THE TWR CTLR WAS TASK SATURATED WORKING COMBINED POS.

Narrative

HOU WAS OPERATING WITH GND CTL AND TWR COMBINED ON 118.7; ARRIVING RWY 12R; DEPARTING RWYS 12R AND 22. WE WERE 2ND IN SEQUENCE TO DEPART RWY 12R; WITH COMPANY IN POS ON RWY 12R; AND ANOTHER COMPANY ACFT IN POS ON RWY 22. TWR CLRED THE COMPANY ON RWY 12R FOR TKOF; THEN CLRED US INTO POS AND HOLD ON RWY 12R WITH A CITATION ON 7 MI FINAL FOR RWY 12R. WE ACKNOWLEDGED AND TAXIED ONTO RWY 12R. TWR THEN CLRED THE ACFT ON RWY 22 FOR TKOF; WITH A L TURN TO HDG 360 DEGS. I REMEMBER SEEING THEIR LNDG LIGHTS ILLUMINATE THE CLOUDS ABOUT THE TIME THEY ENTERED THEIR L TURN OR SLIGHTLY AFTER. AT THIS POINT; THE CAPT AND I BOTH RECOGNIZED THE CONFLICT THAT THIS CREATED: THE DEP OFF RWY 22 WOULD MAKE HIS TURNOUT TO THE N DIRECTLY IN FRONT OF US; DELAYING OUR DEP; WHILE THE CITATION WAS APCHING THE RWY WE OCCUPIED. TWR EVIDENTLY RECOGNIZED THE SIT ABOUT THE SAME TIME WE DID; AND QUERIED THE COMPANY ACFT THAT WAS NOW BEGINNING THEIR L TURN AS TO THEIR ALT. (I DON'T RECALL THEIR REPLY.) TWR THEN CLRED US FOR TKOF RWY 12R; MAINTAIN 1600 FT; FLY HDG 140 DEGS. THE HDG WAS ABOUT WHAT WE WOULD EXPECT DEPARTING TO OUR DEST OFF RWY 12R; THE ALT SEEMED NON STANDARD IN THE EXTREME. I READ BACK THE CLRNC AND WE COMMENCED THE TKOF ROLL; REFING TCASII FOR AWARENESS ON THE ACFT ABOVE AND IN FRONT OF US THAT WE AT THIS POINT COULD NOT SEE. APCHING 1600 FT; TWR CLRED US TO CLB TO 5000 FT AND CONTACT DEP. AFTER CHKING IN; I QUERIED DEP AS TO THE MINIMUM VECTORING ALT IN THAT AREA; AND WAS TOLD IT IS 2200 FT. WHILE I DON'T KNOW ALL THE RULES THAT GOVERN WHAT ALTS HOU TWR MAY ASSIGN THEIR DEPS; THE 1600 FT INITIAL ASSIGNMENT STRUCK ME AS AN EXTREME SOLUTION TO A PREVENTABLE PROB. IF IT COMPLIED WITH THE RULES; THAT'S GOOD. IMMEDIATELY AFTER WE DEPARTED; TWR CLRED ANOTHER ACFT FOR IMMEDIATE TKOF ON RWY 22; WITH THE CITATION ABOUT 2 MI OR LESS ON FINAL. THE ACFT RESPONDED THAT THE CALL SIGN TWR USED WASN'T THEIRS; AND DID HE MEAN FOR (THEIR CALL SIGN) TO DEPART? TWR INITIALLY SAID YES; THEN CHANGED HIS MIND AND SAID; 'NO; HOLD YOUR POS.' AGAIN; I HAVE LIMITED KNOWLEDGE OF STANDARD TWR PROCS; BUT THE PHRASE 'CANCEL TKOF CLRNC' WAS NOTABLE IN ITS ABSENCE. MY CONCERN THAT PROMPTED THIS RPT IS NOT SIMPLY AN UNUSUAL ALT ASSIGNMENT AND SOME POSSIBLY NON-STANDARD ATC PHRASEOLOGY. THE TWR CTLR WAS FAR; FAR TOO BUSY LAST NIGHT CTLING BOTH GND AND TWR; AND THE CTLR WAS NOT UP TO THE TASK. EVEN GETTING PUSHBACK CLRNC WAS DIFFICULT DUE TO THE FREQ CONGESTION. (I FINALLY GOT IT FROM CLRNC DELIVERY AFTER TWR DIDN'T HEAR ME AFTER ABOUT 4 ATTEMPTS.) PEOPLE WHO ARE TASK-SATURATED ARE MORE PRONE TO MAKE MISTAKES; AND I THINK THAT'S WHAT HAPPENED. A MORE EXPERIENCED CTLR MIGHT HAVE BEEN ABLE TO KEEP EVERYTHING STRAIGHT; BUT THE COMBINATION OF THAT NIGHT; THE NUMBER OF ACFT INVOLVED; THIS CTLR; AND THE POS COMBINED; ALL PRODUCED A SIT THAT; IN MY OPINION; YIELDED A MUCH THINNER MARGIN OF SAFETY THAN USUAL.