- · time pressure, possibly low blood sugar, and a change of routine combined to create a potentially bad situation.
- · It was compounded by the fact that the previous rattle had turned out to be trivial, so led to at least a tacit assumption that it would be trivial again.
Tuesday, 29 May 2018
CAUTIONARY TALES ....
ACKNOWLEDGEMENTS: CAA SKYWISE - CHIRP
(Ed. Note: A couple of entries in the latest CHIRP GA Bulletin which show that anyone can suffer lapses in their “professionalism”, so let’s thank these two pilots for baring their souls!)
STARTED TO TAXY WITH TOWBAR ATTACHED
I've been flying the aircraft concerned for years and have many hours in it. Nevertheless, I’m cautious, I stay within my limits, I use the checklists, and I take care with flight planning. This incident – my greatest ever blunder - has rammed home that no matter how experienced and careful, mistakes can still happen.
My usual routine is to phone ahead, to ask the ground crew to pull the aircraft out of the hangar. When I arrive it’s out on the grass, and my first action is to remove the tow-bar before starting on the external checklist.
On this occasion, I had skipped breakfast – and coffee – as I wanted to get airborne as soon as possible for a short local flight before the forecast weather arrived. When I arrived, the aircraft was still in the hangar, so to save time, I did the external checks with the aircraft still indoors. When the ground crew arrived, I helped them pull the aircraft out to the grass, got in, carried out the internal checklist, started the engine, and started to taxy.
My home field is A/G only, and I routinely start up (and often taxy initially) without wearing my headset. This became a habit after an engine overhaul, listening for anything out of the ordinary. A few seconds after I started to move I became aware of a metallic rattling sound, but everything else seemed normal. I probably taxied for a minute or so, trying to figure out what the noise could be. I had had a similar rattle about a year ago, which turned out to be the fire extinguisher clasp which had come loose, so I did spend a number of seconds checking this and looking and feeling for other loose items. Suddenly, something connected in my mind and I realised that I had no memory of removing the tow bar. I shut down immediately.
My blood ran cold when I saw that the tow bar was still attached. I removed it, and inspected both it, and its attachment point on the nose leg. There was, remarkably, no sign of damage, to the nose wheel or leg, or to the tow bar or its attachment points, or, thankfully, to the prop. There was also no sign of a furrow in the soft ground behind the aircraft that might indicate large forces had been applied. Amazingly, I seem to have got away with it.
Obviously, I feel very foolish indeed, but there's quite a lot to take away from this. First a couple of positives:
· I was probably saved because I wasn’t wearing the headset initially, so I heard the rattle
· because I always taxy slowly to protect the nose leg, I wasn’t going fast enough for the bar to either dig in and bend something, or to bounce up and destroy the prop
Now the learning points:
In retrospect, it’s a classic case:
That tacit assumption was a clear symptom of complacency, and in future I would certainly stop taxying immediately, shut down, and carry out a careful inspection, rather than continuing, even for a few seconds, with an unidentified unusual noise.
It is also clear that any change in routine (such as completing part of the pre-flight indoors in this case), or indeed any distraction, should be accompanied by a review of the checklist to ensure that nothing has been missed. I’ll be on the look-out for such situations in future.
We are really grateful for this honest report and excellent analysis of an embarrassing error, which is not an uncommon one. We all need to be aware of the risks associated with changes to a familiar routine and the potential effects of low blood sugar; anyone who has not eaten since the night before is in a state of fast. We are grateful for the opportunity to remind readers to run through the IMSAFE human factors checklist before every flight to ensure they are fit to fly. IMSAFE: Illness, Medication, Stress Alcohol, Fatigue, Eating.
FAILURE TO CHECK BRAKES OFF
The weather was dry. I had two previous flights that day, with no failure to follow correct procedures and without incident. I had drunk just half a pint of beer some hour and a half before the return flight.
Having failed to release the hand-operated brakes before take-off, I did notice that my acceleration was poor despite full RPM on this hard runway. On arrival, I failed again to check brakes-off during the pre-landing checks. My landing seemed normal, and despite the tyre-screech on the hard runway I failed to consider the brakes. The long runway precluded the need to use brakes anyway and it was not until I had taxied to the clubhouse that I noticed that the brakes were still on; and must have been since the holding point prior to take-off. I do believe that this small amount of alcohol, although having no noticeable effect on me, nevertheless did affect my ability to operate the aircraft.
· Drink no alcohol at all.
· Full self-discipline is required when using check-lists and mnemonics.
· The importance of keeping toes off brakes during take-off and landing. This flight might have ended in disaster in another type with more efficient hand-operated brakes.
My subsequent self-discipline has been greatly improved.
Although tiredness on the third sortie of the day may have been a contributory factor, we agree with the reporter’s analysis of the cause and endorse the first lesson learned, “Drink no alcohol at all”.
Although the legal limit for alcohol in pilots’ bloodstream is 20mg per 100ml, one quarter of the UK limit for driving, alcohol impairs performance at any level and the impairment increases exponentially with the amount taken.
Also, many medicines, whether prescribed by a doctor or obtained ‘over the counter’ or by other means (e.g. over the internet) and illicit drugs also impair performance. In the short term (minutes to hours) judgement and decision-making will be affected, there will be an increase in errors and risk-taking behaviour, mood changes, poor co-ordination, tracking and concentration and slow reaction times. Some effects can persist for several days, particularly poor balance and slow cognition.