fcheblog  -

2012-01-16 10:40 | fche blog flying colors

Observed on final approach to KBCB after a bumpy cloudy rainy night flight.

2011-12-19 10:25 | fche blog flying automation reassurance

Freshly released is this investigation final report for an Airbus accident from 2008. In this event, the on-board computers spontaneously messed up during a routine flight, and harshly pitched the plane down for a second or two. This threw around unrestrained passengers and crew in the back, crashing them up to the ceiling. More than a hundred got injured, some seriously. The captain of the plane responded perfectly: declared an emergency, and diverted to the nearest suitable airport. He did not trust the avionics any more:

He then flew the aircraft without the autopilot or autothrust engaged, and using the standby instruments, for the remainder of the flight.

The bit that bugs me more is the root-cause-analysis and correction of the bugs in the system. The final report unnervingly qualifies this:

The failure mode was probably initiated by a single, rare type of internal or external trigger event …
The spikes in the ADR parameters were probably introduced within the CPU module …
A much more likely scenario was that a marginal hardware weakness of some form made the units susceptible to the effects of some type of environmental factor, which triggered the failure mode.

It goes on like that. They’ve done some impressive analysis of the systems, but the there is quite a collection of maybes and probablys.

But be reassured:

The occurrence was the only known example where this design limitation led to a pitch-down command in over 28 million flight hours on A330/A340 aircraft. ...
It is widely accepted that not all the potential failure modes and failure scenarios for complex systems can be identified in practice, and fault-tolerant design features are included in a system to reduce the risk of such problems. ...
The ADIRU manufacturer conducted a ‘theoretical analysis’ of the potential for a single event upset (SEU) on the LTN-101 ADIRU. The overall result of this analysis was that [...] the ADIRU still met the aircraft manufacturer’s safety objectives …
As a result of this redesign, passengers, crew and operators can be confident that the same type of accident will not reoccur.

It’s an uneasy situation. Having a sense of how much technology and effort goes into this sort of machinery, it’s clear that there are failure scenarios that we don’t know we don’t know. And yet we fly.

2011-08-08 21:57 | fche blog flying heart beat frequency

When one’s life depends on the proper operation of a complex mechanical device, it pays to be attentive.

2011-05-27 10:54 | fche blog flying stall inexperience

According to this new BEA report, the last few minutes of Air France 447 were spent with the aircraft plummeting in deep stall, with the pilots exacerbating the situation by nose-up pitch controls. Just like Colgan 3407. It sounds a though big iron pilot practice needs more focus on basic stick & rudder flying. Mechanical emergencies are drilled non-stop, and have become relative non-events when they occur in real life. May aerodynamic emergencies become as well-practiced sometime.

2011-01-12 00:53 | fche blog flying amateur flying career

My near-decade of private piloting experience suggest three distinct phases of the activity.

2010-11-14 07:38 | fche blog flying positive side of TSA patdowns

It’s been easy for me to have given the benefit of doubt to US TSA folks in their efforts to keep US flying passengers safe. They have in some ways an impossible job. And, being spoiled with private aviation, I am unlikely to be subjected to the full monty of the TSA any time soon.

But stories like this one and this one and this one make one wonder just what the end game is here. How much are people expected to put up with, before throwing their hands up, and giving up on commercial air travel? (Only an aggressive few may ever sue.)

Then it struck me. Perhaps people giving up on commercial air travel is a not-unfavourable outcome, as far as the current US federal government is concerned. After all, it would cut down on flying, which would cut down on flights, which would cut down on fuel consumption. Wouldn’t that be a simply splendid counter-manoeuvre to the failure of efforts to curteil that horrible CO2 gas?

2010-06-23 21:44 | fche blog flying dive dive dive

Last night, I renewed my IFR privileges for another two years, after passing a flight test with my friend Charlie Rampulla. One mistake I made may be interesting reading for other pilots.

2010-05-17 16:16 | fche blog flying criss cross pause

During last night’s return flight from KCMH, there was a brief air-traffic-control “teaching moment”.