Departing IFR aircraft overtook a preceding IFR aircraft which resulted in less than standard separa...

Attributes
ACN	174844
Time
Date	199104
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : bed
State Reference	MA
Altitude	msl bound lower : 133 msl bound upper : 1500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bos tower : bed tower : dtw
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	climbout : takeoff climbout : intermediate altitude
Route In Use	departure other enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	climbout : intermediate altitude climbout : takeoff
Route In Use	departure other enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
ASRS Report	174844
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : developmental
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Miss Distance	horizontal : 15000 vertical : 900
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

While training a developmental on local control, 2 IFR aircraft called for departure. Small aircraft X was cleared to depart off runway 29 at XX36Z and assigned an initial heading of 250 degrees. When small aircraft X was 2 NM from the departure end of runway 29 (as determined by BRITE conrac in the tower cabin attendant), small aircraft Y was issued a 250 degree heading and cleared to depart at XX41Z. (Considering that runway 29 is more than 1 NM in length, I considered this an application of paragraph 3-104 of 7110.65F.) apparently, small aircraft Y overtook small aircraft X after he was switched over to bos approach frequency. When I realized that sep was probably going to decrease to less than 3 NM (7110.65F, paragraph 5-72 a.1), I advised bos approach (through my flight data personnel) that he had permission to turn small aircraft Y as he felt necessary.

Original NASA ASRS Text

Title: DEPARTING IFR ACFT OVERTOOK A PRECEDING IFR ACFT WHICH RESULTED IN LESS THAN STANDARD SEPARATION (RADAR).

Narrative: WHILE TRNING A DEVELOPMENTAL ON LCL CTL, 2 IFR ACFT CALLED FOR DEP. SMA X WAS CLRED TO DEPART OFF RWY 29 AT XX36Z AND ASSIGNED AN INITIAL HDG OF 250 DEGS. WHEN SMA X WAS 2 NM FROM THE DEP END OF RWY 29 (AS DETERMINED BY BRITE CONRAC IN THE TWR CAB), SMA Y WAS ISSUED A 250 DEG HDG AND CLRED TO DEPART AT XX41Z. (CONSIDERING THAT RWY 29 IS MORE THAN 1 NM IN LENGTH, I CONSIDERED THIS AN APPLICATION OF PARAGRAPH 3-104 OF 7110.65F.) APPARENTLY, SMA Y OVERTOOK SMA X AFTER HE WAS SWITCHED OVER TO BOS APCH FREQ. WHEN I REALIZED THAT SEP WAS PROBABLY GOING TO DECREASE TO LESS THAN 3 NM (7110.65F, PARAGRAPH 5-72 A.1), I ADVISED BOS APCH (THROUGH MY FLT DATA PERSONNEL) THAT HE HAD PERMISSION TO TURN SMA Y AS HE FELT NECESSARY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Departing IFR aircraft overtook a preceding IFR aircraft which resulted in less than standard separation (radar).