ZID developmental uses the altitude leaving rule and ends up having a loss of separation.

Attributes
ACN	1220870
Time
Date	201411
Local Time Of Day	1801-2400
Place
Locale Reference	ZID.ARTCC
State Reference	IN
Environment
Light	Night
Aircraft 1
Make Model Name	Medium Transport Low Wing 2 Turbojet Eng
Flight Phase	Descent
Flight Plan	IFR
Aircraft 2
Make Model Name	Large Transport
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	Enroute Trainee
Qualification	Air Traffic Control Developmental
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Narrative:

Aircraft X was at FL350; landing lex. Aircraft Y was handed off to me from sector 95 at FL360. I descended aircraft X to FL240. When aircraft X was observed leaving FL350; I descended aircraft Y to FL350. The 2 aircraft went into conflict alert about 10 seconds later. Aircraft Y said he had an RA and was climbing. I called the traffic to aircraft Y and within 15 seconds aircraft Y said the RA was over and he was returning to FL350.the only recommendation I can think of is to make sure the aircraft are using the same rate of descent. The aircraft involved were comparable in descent profiles but aircraft X obviously was not maintaining normal rate of descent. With that being said; the rule in chapter 5 of the 7110.65 was applied correctly.

Original NASA ASRS Text

Title: ZID Developmental uses the altitude leaving rule and ends up having a loss of separation.

Narrative: Aircraft X was at FL350; landing LEX. Aircraft Y was handed off to me from Sector 95 at FL360. I descended Aircraft X to FL240. When Aircraft X was observed leaving FL350; I descended Aircraft Y to FL350. The 2 aircraft went into conflict alert about 10 seconds later. Aircraft Y said he had an RA and was climbing. I called the traffic to Aircraft Y and within 15 seconds Aircraft Y said the RA was over and he was returning to FL350.The only recommendation I can think of is to make sure the aircraft are using the same rate of descent. The aircraft involved were comparable in descent profiles but Aircraft X obviously was not maintaining normal rate of descent. With that being said; the rule in Chapter 5 of the 7110.65 was applied correctly.

Data retrieved from NASA's ASRS site 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.