B737-800 maintenance technician reported that while replacing the rudder; a restraining sling broke ...

Narrative:

During installation of rudder; the sling broke loose at the shackle on the left hand side; swinging the rudder to the right into the man lift myself and a fellow mechanic were in. Luckily; before the incident the other two mechanics on the other side had managed to stick a bolt in the lower most hinge. From that point; we were instructed by the supervisor to try and secure the rudder to avoid any further damage or potential injury to personnel. Our hangar is not equipped to perform rudder changes on 737-800 as we found out while trying to jack the nose per the engineering authorization (ea); which tells to use aircraft maintenance manual 07-11-21 to use the crane indoors. However; before the aircraft could get into the position it is needed; the jack would come unseated. At one point; the aircraft almost rolled off the jack.many of my fellow mechanics as well as myself expressed concern that this job should not have been scheduled for our base as we were told that [another base] was capable and was supposed to be the base for 737-800 rudder changes. Under the failed attempts; our lead pulled the aircraft out to the wash rack and the install was continued. Shortly after the incident and during the securing portion it started to heavily down pour. The following day when we returned to work; we were informed that there had been no damage to the rudder or aft structure to the vertical.

Original NASA ASRS Text

Title: B737-800 Maintenance Technician reported that while replacing the rudder; a restraining sling broke loose; subsequently swinging the rudder into their working platform.

Narrative: During installation of rudder; the sling broke loose at the shackle on the left hand side; swinging the rudder to the right into the man lift myself and a fellow mechanic were in. Luckily; before the incident the other two mechanics on the other side had managed to stick a bolt in the lower most hinge. From that point; we were instructed by the supervisor to try and secure the rudder to avoid any further damage or potential injury to personnel. Our hangar is not equipped to perform rudder changes on 737-800 as we found out while trying to jack the nose per the Engineering Authorization (EA); which tells to use Aircraft Maintenance Manual 07-11-21 to use the crane indoors. However; before the aircraft could get into the position it is needed; the jack would come unseated. At one point; the aircraft almost rolled off the jack.Many of my fellow mechanics as well as myself expressed concern that this job should not have been scheduled for our base as we were told that [another base] was capable and was supposed to be the base for 737-800 rudder changes. Under the failed attempts; our lead pulled the aircraft out to the wash rack and the install was continued. Shortly after the incident and during the securing portion it started to heavily down pour. The following day when we returned to work; we were informed that there had been no damage to the rudder or aft structure to the vertical.

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.

Attributes
ACN	1523478
Time
Date	201802
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Parked
Component
Aircraft Component	Rudder
Person 1
Function	Technician
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Ground Event / Encounter Object

B737-800 maintenance technician reported that while replacing the rudder; a restraining sling broke loose; subsequently swinging the rudder into their working platform.