As a safety consultant I quite often consider "What ifs" when carrying out risk assessments, some people think some if my scenarios are a little over the top but I do it anyway. How about a risk assessment on a tower crane in a city centre development, among the potential hazards are the usual considerations for working at height with a rescue plan, correct loading and securing loads for lifting etc. How about the potential for a helicopter crashing into the crane and bursting into flames, the chopper and crane breaking up and scattering burning materials onto members of the public on the ground, resulting in car fires, people potentially injured and in the Thames, fatalities both from the chopper and on the ground. If I produced that scenario in a safety talk I believe it would have been the subject of a few jokey remarks to say the least. http://edition.cnn.com/2...icopter-crash/index.html

I believe it depends on what task your 'what ifing' and the potential for harm. I have seen risk assessment for what if's on using a micro wave oven that took 4 pages, because you didn't just have the usual scolds, plate being hot etc, they had then gone into spilt on floor trip hazard then or the risks with mopping , COSSH etc for chemicals, then they had the cleaning of the micro wave and the potential for this that and the other. In the end no-one paid much attention to the R/A's that were being produced for this reason and thought H&S or at least that practitioner was joking.

I think we have to make a discrimination between managing and assessing the foreseeable risk arising from the task at hand and those less likely emergency and disaster scenarios. There's work and workplace risk assessment and there's Risk Management, Emergency Planning, Business Continuity and Disaster Recovery. I can't really imagine a situation where Site Induction would include discussion of what to do if a plane drops from the sky?

For forum users who might not have seen/heard the UK news for the past 2-3 hours it seems pertinent to put the helicopter crash scenario into context by mentioning that such an event happened in South London earlier this morning when a helicopter apparently collided with a tower crane. Though some people might smile at some 'what if' scenarios mentioned during training, etc., and think them to be extreme, the point is that some of the scenarios can happen even though their statistical incidence or probability is very low. For example, during training for headteachers/managers from my former employer's schools, I've sometimes mentioned the risk of aircraft crashing on or near their schools while leaving or approaching a major airport some miles away. Though the likelihood of such an event is extremely low (and there's nothing that the schools can do about preventing one), the trainees generally didn't regard it as impossible because an aircraft did crash in the area during the 1960s.

I don't now the process by which the aviation authorites were informed - presumably the crane erectors would have knowledge/experience of any requirements - but notified they certainly were. There was a NOTAM (Notice to Airmen) issued about it: HIGH RISE JIB CRANE (LIT AT NIGHT) OPR WI 1NM 5129N 00007W, HGT 770FT AMSL (VAUXHALL, CENTRAL LONDON), OPS CTC 12-10-0429/AS 2.

Thanks, wclark. I guess the CDM bit would just ensure that the notification had been done. It must be standard requirement if you put anything above a certain height.

In offshore construction we suspend all crane ops when we have a chopper coming in. I'm not sure how that would work in civil avaiation/construction.

quote=safetyamateur]Going back to the original question. Not so sure that collision of aircraft would be part of the crane risk assessment. More likely from the aviation angle which would set up the requirement for construction jobs to be notifiable to aviation authorities.

Yes it would Ron if you worked at an Airport!

Our site is in the middle of the country and the countryside is very flat. It is regularly over flown by the RAF and other air forces. We have mentioned this to the MoD several times and they have said their plans always stick to the rules and do not come within 200 m of the ground. Just before Christmas we had a mobile crane on site (the jib was about 50 m, not particularly high but higher than anything on the site. One morning a jet comes over the site and the project manager is convinced that the jet had to take evasive steps to stop colliding with the crane. We note this as an incident and we reported this to the MoD who said the plane was at last 200 m from the ground and there was no danger of a collision. We suspect the pilot was surprised to see the crane in the middle of the countryside and decided to jink at the last minute just in case. It gave our guys on the ground a bit of a fright. Of course we treated this as a bit if joke and we never bothered to include this in risk assessment as it is obviously not foreseeable for an aircraft to crash in to a crane.

I think we need to be careful of hindsight bias. The probability of a helicopter hitting a tower crane over London...is so remote that it would not even register on a RA. Yes it can happen, indeed it did. However, it does not change the probability. The term is improbable but not impossible.

Due to foreseeable reasons ie 'the river is defined route for helicopters', then the probability will increase. Hence it may be prudent to include a RA and appropriate controls.