SPD LIM flag appeared on both Capt’s and FO’s EADIs. 737-3/4/500

Defect: SPD LIM flag appeared on both Capt’s and FO’s EADIs.

Resolution: Apparently the barometric pressure was above 31.03 (the max that the barometer can handle on a 737-400. We had to have an EA cut from Boeing allowing the operation of aircraft above max ambient pressure.

Story: I was dispatched to go fix this SPD LIM flag. However the SMC’s would show no faults on the BITE. the SMYD would show no faults. Thus while continuing the troubleshooting, another aircraft came in and had the same flag, making it now effective that separate aircraft had the same problem, in the same location (OTZ). Company sent a third aircraft to deliver parts and equipment. The first two aircraft were 737-400 Combi (half cargo, half passenger config), this third aircraft was a 737-400 (full passenger config). The third aircraft had the same SPD LIM flag.

After receiving relief from boeing, as soon as we took off, the crew noticed the flag went away before they had a chance to fully retract the gear.

Hope this helps. Thanks to Samuel H. for his input.




