Loss of the Ethiopian Airlines Boeing 737 Max 8, just a few minutes after take-off, is likely to stir disquiet over the re-engined type which emerged during the probe into a Lion Air Max 8 accident.
Ethiopian Airlines has five Max 8s in its fleet and the aircraft involved (ET-AVJ) was only delivered to the carrier in mid-November last year.
Some two weeks before the Ethiopian delivery a Lion Air Max 8 – which itself was less than three months old – crashed into the sea some 12min after taking off from Jakarta on 29 October.
Indonesian investigators have yet to establish conclusions about the Lion accident but have already found that the aircraft started experiencing flight-control problems within 2min of becoming airborne, with fluctuating altitude and automatic nose-down trimming as it attempted to climb to its cruise level.
Investigators determined that the jet had suffered a number of airspeed and altitude indication problems over the three days prior to the crash, and that the ill-fated flight had shown up inconsistencies with the aircraft’s angle-of-attack sensor readings.
Within a few days of the accident Boeing issued a notification to 737 Max operators pointing out that, in manual flight, erroneous angle-of-attack data could cause the pitch-trim system to trim the horizontal stabiliser nose-down unless the crew intervened to activate stabiliser trim cut-out switches.
The US airframer emphasised the symptoms of erroneous angle-of-attack information – which included possible airspeed and altitude disagreement – and stressed the procedures for dealing with nose-down stabiliser trim.
Boeing says it is “aware” of the emerging information about the Ethiopian accident and says it is “closely monitoring the situation”.
There is no immediate evidence that the Ethiopian aircraft, operating flight ET302 to Nairobi on 10 March, suffered similar problems to the Lion Air jet, although it also came down shortly into its initial climb, having taken off some 6min earlier from Addis Ababa’s runway 07R.
Meteorological data from Addis Ababa around the time of the accident indicates good visibility and no adverse weather conditions.
Ethiopian has 30 737 Max jets on order. It received its first at the beginning of July last year. The airline already operates a fleet of 737-800s and -700s and recently took delivery of its first converted 737-800SF freighter.