Could you cite said studies? I studied aerospace engineering in college and was taught that there is no evidence of this beyond a pilot and some air hostesses, at some point a few decades ago, hypothesising that some avionics error was caused by passenger electronics.
There is a comprehensive database of civil air traffic accident, compiled with IATA, on http://planecrashinfo.com/database.htm. I have yet to see anything cell phone-related.
A quick google search reveals a study including a case where the pilot in cooperation with the passenger identified his laptop as causing interference on navigation instruments.
Is it really too much to ask to do a quick Google search?
Yes, anybody can do a google search. You can also do a google search for "9/11 was an inside job" and "JFK killed Marilyn." Doesn't mean that the first google hit is a study that is reliable, repeatable, or even factual.
I didn't tell you to look at the first Google hit, did I? But if you're going to voice your opining, I do expect a minimal amount of effort to educate yourself. You can easily find reports hosted by for instance NASA, and to discredit those you have to thing that pilots are imagining things or part of a worldwide conspiracy.
However, most people here seem content to disregard any evidence that may contradict their beliefs.
The real reason why PEDs are still banned are because neither FAA, airlines or manufacturers have been willing to perform comprehensive studies in order to determine the effects on planes.
The reason we have WiFi access on planes nowadays is because very detailed and expensive studies have been done, and improved shielding has been added to certified planes. Apparently such studies are underway, but risk-aversion in the aviation industry means nothing is going to change before the results of those studies are in.
I'm a private pilot and I leave my cell phone on as a safety measure in case the radio breaks down. I disable cell data and try to place it away from the avionics so I get a minimu amount of noise in my headset. However, if I was instrument rated, I wouldn't attempt an instrument approach in minimal weather conditions with my cell phone on. I can't conclusively prove that my phone is incapable of influencing the instruments, but I'd rather not find out "the hard way".
I found this study and at the end is an interesting summary from the RTCA:
"Those findings indicated that the probability of interference to installed aircraft systems from PED, singly or in multiples, is extremely slight. However, the slight possibility of interference to aircraft navigation and information systems during critical phases of flight, e.g., takeoff and landing, should be viewed as potentially hazardous and an unacceptable risk for aircraft involved in passenger carrying operations. Therefore, the committee recommends that the use of PEDs be restricted during certain critical phases of flight."
This study says we cannot be sure that PEDs are safe. The original comment, that "there are many recorded incidents of interference [which] happened, and were documented by the FAA", is false. There is a slight potential for interference and we hypothesise that this interference could be unsafe.
