Failure in warning system led to Sumburgh plane’s emergency landing at Aberdeen

AIR ACCIDENT investigators have issued a report into an incident that saw an Eastern Airways plane bound for Sumburgh with 18 passengers turn around and make an emergency landing in Aberdeen in February.

The Jetstream 4100 twin engine passenger plane suffered a failure of its primary and secondary nose landing gear (NLG) indicators that showed the aircraft’s nose gear was not locked down for landing.

That forced the pilot to return to Aberdeen where the aircrew prepared passengers for an emergency exit of the aircraft in the expectation the nose gear would collapse on landing.

Ground staff could see the nose gear extended as the plane circled several times but the pilots had no way of knowing if it was locked or if the warning system was faulty.

Emergency services braced for action at the airport. The plane landed safely but passengers still had to make an overwing disembarkation as the pilot was not sure that the NLG was sound and it was deemed safer to use the emergency exits rather than use the forward stairs in case of collapse.

The Air Accident Investigation Branch (AAIB) report says that the failure of the “primary downlock harness” was probably caused by vibration rather than environmental exposure.

“To verify the condition of the fleet, the operator [Eastern Airways] has inspected all the other harnesses fitted to their aircraft and no other failures were found, so they are considering it an isolated event,” it adds.

“Based upon the information from two indication systems that the NLG was not ‘down and locked’, the crew reviewed possible landing scenarios and planned their actions based upon a landing with a NLG collapse.

“This did not happen; the crew followed their plan and successfully evacuated all passengers and crew through the overwing exits with no injuries,” the report says.

It adds that the aircraft manufacturer had since taken action to prevent mis-rigging of the warning system and has revised the aircraft manual to improve clarity and efficiency of checklists.

As well as the one-off inspections of the nose landing gear warning systems, Eastern Airways is to carry out repeat inspections every 600 flight hours and update all its emergency and abnormal checklists in line with the manufacturer’s revision.