A320, vicinity Addis Ababa Ethiopia, 2003

Summary: 

On 31 March 2003, an A320, operated by British Mediterranean AW, narrowly missed colliding with terrain during a non-precision approach to Addis Ababa, Ethiopia.

Event Details
When: 
31/03/2003
Event Type: 
Day/Night: 
Night
Flight Conditions: 
IMC

18678

Flight Details
Aircraft: 
Operator: 
Type of Flight: 
Public Transport (Passenger)
Intended Destination: 
Actual Destination: 
Take-off Commenced: 
Yes
Flight Airborne: 
Yes
Flight Completed: 
Yes
Phase of Flight: 
Descent
Location
Location - Airport
Airport: 
CFIT
Tag(s): 
Into terrain, Lateral Navigation Error, IFR flight plan
Outcome
Damage or injury: 
No
Non-aircraft damage: 
No
Non-occupant Casualties: 
No
Off Airport Landing: 
No
Ditching: 
No
Causal Factor Group(s)
Group(s): 
Air Traffic Management
Safety Recommendation(s)
Group(s): 
Aircraft Airworthiness, Air Traffic Management
Investigation Type
Type: 
Independent

Description

On 31 March 2003, an AIRBUS A-320, operated by British Mediterranean AW, narrowly missed colliding with terrain during a non-precision approach to Addis Ababa, Ethiopia.

Synopsis

The following is an extract taken from the UK AAIB report into the incident:

"[The] A320..on a flight from Alexandria…to Addis Ababa, Ethiopia, carried out two approaches using Addis Ababa [VOR] and associated…DME. On the second approach the aircraft crossed over a ridge of high ground in…IMC and came within 56 feet of terrain at a location 5 nm to the northeast of the airport. As the aircraft croosed the ridge the crew, alerted a few seconds earlier by a radio altimeter (RA) height callout, carried out a go-around: at the same time the…EGPWS generated a "TOO LOW TERRAIN" aural alert.

The investigation determined that the antenna of the ADS VOR had suffered water ingress and was not functioning correctly. The correct maintenance procedures for the ADS VOR/DME and its associated monitoring equipment were not followed.

The aircraft received erroneous information from the ADS VOR which was fed to the flight deck VOR display, the FMS, the navigation displays and the EGPWS computer with its associated Terrain Awareness Display (TAD). A single common position source error thus adversely affected all these apparently independent navigation/situational awareness systems. The existing certification standards for the aircraft navigation systems were met but were not sufficient to protect against this problem."

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