EASA SIB 2023-09R1
NORTHROP GRUMMAN LITEF GmbH - Erroneous Computation of Flight Path Acceleration and Potential Vertical Speed
Summary
EASA Safety Information Bulletin 2023-09R1 is an informational bulletin addressing erroneous computation of flight path acceleration and potential vertical speed in Northrop Grumman LITEF GmbH LCR-100, LCR-110, and LCR-350B Attitude and Heading Reference Units (AHRU) and Global Navigation Satellite System Aided Inertial Reference Units (GIRU). The affected units include specific part numbers such as LCR-100 AHRU P/Ns 145130-1000-XXX through 145130-3000-XXX, LCR-110 GIRU P/Ns 153120-1000 013 2315 and 153120-1001 013 2315, and LCR-350B AHRU P/N 154200-2000 001 1001. This bulletin informs aviation stakeholders about the anomaly without mandating corrective action.
What Changed
This revision updates EASA SIB 2023-09 by referencing Service Bulletin 153121-0001-845 Revision B, which corrects previously misquoted part numbers. It clarifies the affected part numbers and confirms that the erroneous flight path acceleration and potential vertical speed data outputs occur under specific flight conditions. No new mandatory actions or airworthiness directives are introduced.
Why It Matters
The bulletin highlights that certain ARINC 429 output labels for flight path acceleration and potential vertical speed from the affected units are erroneous during turns and deceleration phases. Although no unsafe conditions have been reported in actual operations, operators and maintenance personnel need awareness to avoid reliance on these specific data outputs, ensuring accurate flight data interpretation and system integration.
What To Do
Type certificate and supplemental type certificate holders should analyze whether aircraft systems use the affected ARINC 429 labels from the impacted units. If affected, they must report findings to EASA and inform operators accordingly. No mandatory compliance deadlines are specified, but stakeholders are encouraged to contact Northrop Grumman LITEF GmbH for further technical support and to monitor any future updates.