SL0810-01b2.doc Page 1 of 3 

 Nightsun® XP Searchlight 

Safety and Service Bulletin # SL 0810-01 

Amendment # 2 Date:09/24/2010 

Subject: Gimbal Azimuth Top Hex Nut 

Affected Products: 

Nightsun® XP Gimbal Assemblies (See Exhibit A for specific part numbers) used on Nightsun®

XP Systems, including In Flight Change Over (IFCO) equipped systems. 

WARNING: TO AVOID A POTENTIALLY DANGEROUS SITUATION 

WHICH COULD CAUSE PROPERTY DAMAGE, ENSURE THAT THE 

GIMBAL ASSEMBLY IS INSPECTED AND / OR REPLACED AS 

DESCRIBED IN THIS BULLETIN. 

Dear Nightsun® XP Searchlight Product User: 

Under certain conditions, the Gimbal’s Azimuth Top Hex-Nut may become loose. The Gimbal’s 

Azimuth Top Hex-Nut is located internal to the Gimbal under the top Shroud Cover in the dovetail 

mount location. A loose nut could cause; a gap between rubber edging of the top Shroud and the 

Gimbal frame; degradation of pointing accuracy and stability performance; and pose excessive 

vibration on the aircraft. If the nut were to entirely disengage, the Searchlight/Gimbal could 

potentially disconnect from the aircraft and remain attached solely by the internal cable harness. 
Spectrolab, Inc. Safety and Service Bulletin # SL 0810-01 dated 08/12/10 

 Amendment # 2 dated 09/24/10 

SL0810-01b2.doc Page 2 of 3 

What you should do: 

Perform the inspection procedure described in this letter daily. 

1. Ensure the Searchlight/Gimbal is vertically mounted to a fixed location. 

2. Visually inspect the Gimbal for a gap between the Top Shroud rubber edging (P/N 033381) 

and the Side Covers (P/N 033286). When the Gimbal’s Azimuth Top Hex-Nut is properly 

fastened, the edging should be in physical contact with the Side Covers. 

3. Try to move the Searchlight laterally (reference figure below). No gap should appear 

between the Top Shroud rubber edging (P/N 033381) and the Side Covers (P/N 033286) 

and no play should be felt. 

4. If a discrepancy is encountered, remove the system from the aircraft and return to 

Spectrolab immediately for compliance updates described in the Corrective Action section 

of this letter. If a discrepancy is not encountered, please contact Spectrolab to schedule the 

compliance updates. 

Spectrolab, Inc. 

Attn: ILS Repair Station 

12500 Gladstone Avenue 

Sylmar, CA 91342-5373 

(818) 898-2807 

 

Rubber edging 

should be making 

contact with Side 

Cover and a gap 

should not be 

present here

Gap should not 

appear when 

pressure is 

applied on the 

Side Covers when 

trying to create 

side-to-side 

motion from 

either side. 
Spectrolab, Inc. Safety and Service Bulletin # SL 0810-01 dated 08/12/10 

 Amendment # 2 dated 09/24/10 

SL0810-01b2.doc Page 3 of 3 

Corrective Action: 

To prevent the Gimbal azimuth top hex nut from coming loose a design change introduces two 

positive locking mechanisms. In addition to a torque value of 120-140 ft-lbs applied to the nut 

and Loctite® 262 applied to the threads of the shaft, the nut will have two locations for safety 

lock wire. 

In order to track all Nightsun® XP gimbals that are in conformance the Gimbals modified, as 

described above, will be re-identified as either 033295-3 or 033295-4 (white light and IFCO 

light, respectively). A new revision will be assigned to the top level system part numbers, 

specified in Exhibit A, reflecting the modified and compliant Gimbal. 

Exhibit A – Affected System Part Numbers

System P/N Nomenclature Affected Revisions 

033338 Nightsun® XP Searchlight System D and prior 

033338-3 Nightsun® XP Searchlight System D and prior 

033338-4 Nightsun® XP Searchlight System D and prior 

033704 IFCO Nightsun® XP Searchlight System C and prior 

033704-1 IFCO Nightsun® XP Searchlight System C and prior 

For questions on this Service Bulletin or to return the system, please call our Customer Service 

Department at 1-800-936-4888 for instructions and/or a Return Material Authorization (RMA) 

number. 

Emilio Quezada 

Director of ILS Operations 

Spectrolab, Inc. (A Boeing Company)