Travel: October 2019 Archives

Boeing wrongly assumed pilots would quickly trim out MCAS - Flight Global

"Boeing incorrectly predicted the manner in which 737 Max pilots would respond to the activation of the Manoeuvring Characteristics Augmentation System, by assuming they would initially pull back on the control column and then trim out the force to maintain level flight....

"Failure to re-trim the aircraft during a series of repeated MCAS activations would result in the stabiliser gradually shifting to its maximum deflection, with the crew attempting to keep the nose up with increasing force on the control column.

"When the 737 Max was being developed, simulator testing during functional hazard assessment 'never considered' the scenario of repetitive MCAS activation incrementally driving the stabiliser to its maximum limit.

"Boeing had believed repetitive MCAS activations to be 'no worse' than a single activation, because of its assumption that the pilots would trim out the forces each time, says the inquiry. It had also assumed that the crew would respond correctly, and within 3s."

Boeing's MCAS test did not simulate other cockpit effects - Flight Global

"Indonesian investigation authority KNTK says Boeing's preliminary hazard assessment of MCAS, carried out on a full-flight simulator in 2012, examined crew responses to uncommanded MCAS activation 'regardless of underlying cause'.

"This focus on the pilots' response to MCAS - rather than the reason MCAS might be triggered - meant that specific failure modes 'were not simulated', says the inquiry, and therefore neither were the cockpit effects of those failure modes.

"KNKT says a failure such as erroneous angle-of-attack sensor data, leading to unreliable airspeed alerts, stick-shaker activation, and other alarms in the cockpit were not part of the simulation....

"[A post-crash simulator] exercise [recreating cockpit conditions] found that crews could not maintain altitude with control column force alone if short activation of electric trim resulted in an accumulating mis-trim from the MCAS nose-down commands.

"'Repeated MCAS activations increased the flight crew workload and required more attention to counter it,' says the inquiry. Communicating with air traffic control was 'distracting', it adds, and crews found the non-normal checklist 'hard to get through'."

The James Herriot centenary: a vet who changed his profession - Telegraph

"...there's a phenomenon known as "the Herriot effect" that's blamed for the huge increase in popularity of the career as a vet which started in the mid-Seventies. Back in the sixties, a typical vet student was son of a vet or a farmer, and there was no need for academic prowess to get a place at vet school. By the time I was a student in the early eighties, most of us had no rural background and straight "A"s were needed in school exams. The gender balance changed too, with females now making up 80 per cent of new veterinary graduates. The glamorisation of the job by Herriot has played a role in these changes. Budding vet students soon learned that it didn't help their chances of success to mention the books in selection interviews....

"When I took up my first job as a mixed practice vet, in the Scottish borders, I experienced many parallels with his books: I even gleaned useful practical tips from them (such as pouring sugar onto a cow's prolapsed uterus to shrink it down before stuffing it back in). I had the same types of experiences with farmers, both good (hearty breakfasts in the farmhouse after a successful calving) and bad (I used Herriot's trick of reversing the car into the farmyard to allow for a rapid exit in an uncomfortable situation).

"I ended up leaving farm practice, disheartened by the trend away from smallholdings towards large scale production, ending up attending to pets as my full time job. Herriot's tales ring equally true in this line of veterinary work: every small animal vet has clients reminiscent of 'Mrs Pumphrey' and her beloved Pekes, and we've all had occasions when we have difficulty understanding what a client is saying because of a local brogue (in Herriot's case it was a strong Yorkshire dialect, but there are variations on this theme across the world)."

World of James Herriot, Thirsk, Yorkshire, England

If you're ever in Yorkshire, the James Herriot Museum in Thirsk, in Alf Wight's home and veterinary surgery, is well worth a visit. It's about a half-hour north of York. It's a combination museum: The life and career of Alf Wight, domestic life in 1930s Yorkshire, the history of veterinary practice, and the history of the TV series. We spent a fascinating morning there.